using adams/car ride - md adams 2010
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Welcome to Adams/Car Ride
Adams/Car RideIntroduction
2
IntroductionAdams/Car Ride, part of the MD Adams 2010® suite of software, is a plugin to Adams/Car. You can use Adams/Car Ride to model and simulate the ride quality of ground vehicles. It contains modeling elements important for ride quality that you can use in Adams/Car models. You can also analyze the modeling elements independently from other systems using a modeling-element test rig.
In addition, Adams/Car Ride includes a four-post test rig for four-wheeled Adams/Car vehicle models. The four-post test rig supports a variety of time-domain analyses, as well as frequency-domain analyses with Adams/Vibration.
About Adams/Car RideUsing Adams/Car Ride, you can quickly create Adams/Car assemblies of suspensions and full vehicles, including Adams/Car Ride-provided components important for ride quality, and then analyze them to understand their performance and behavior.
The Adams/Car Ride components are:
• Monroe damper
• Hydromount
• Frequency-dependent bushing
You can analyze each component independently from other systems using a component test rig. You can also use a parameter identification tool for the hydromount component, to quickly determine model parameters that will accurately reproduce test data.
Using the Adams/Car Ride four-post test rig for four-wheeled Adams/Car vehicle models you can simulate a vehicle traveling over a rough road or simulate a vehicle on a real four-post shaker test machine. You can play displacement or force RPC III file data into the test rig, make your own bumps with table-lookup functions and drive over them, or create and drive over a road-profile surface using a mathematical model for generating road roughness. In the time domain, the four-post test rig also supports sinusoidal sweeps (displacement, velocity, acceleration, or force) and arbitrary Adams/Solver functions.
Learn more about Referencing Test Data.
Benefits of Adams/Car RideAdams/Car Ride enables you to work faster and smarter, letting you have more time to study and understand how design changes affect vehicle performance.
Using Adams/Car Ride you can:
• Explore the performance of your design and refine your design before building and testing a physical prototype.
3Welcome to Adams/Car RideIntroduction
• Analyze design changes much faster and at a lower cost than physical prototype testing would require. For example, you can change springs with a few mouse clicks instead of waiting for a mechanic to install new ones in your physical prototype before re-evaluating your design.
• Vary the kinds of analyses faster and more easily than if you had to modify instrumentation, test fixtures, and test procedures.
• Work in a more secure environment without the fear of losing data from instrument failure or losing testing time because of poor weather conditions.
• Run analyses and what-if scenarios without the dangers associated with physical testing.
• Perform a repeatable set of tests on a global basis, ensuring that you work with common data, tests, and, most important, results.
Starting Adams/Car RideBecause Adams/Car Ride is a plugin to Adams/Car, you first start Adams/Car and then load Adams/Car Ride.
In the Windows environment, you start Adams/Car from the Start button. In the UNIX environment, you start Adams/Car from the Adams Toolbar. For information, see the Running and Configuring online help.
To start Adams/Car Ride:
1. Start Adams/Car as explained in Starting Adams/Car.
2. From the Tools menu, select Plugin Manager.
3. In the list of plugin names, find Adams/Car Ride, and then select one or both of the following:
• Load - Loads Adams/Car Ride in the current session.
• Load at Startup - Instructs Adams/Car to load Adams/Car Ride in all future Adams/Car sessions.
4. Select OK.
Adams/Car loads Adams/Car Ride. The interface now includes a new menu, Ride.
Adams/Car RideRunning Analyses
4
Running Analyses
Introducing AnalysesAdams/Car Ride allows you to create virtual prototypes of vehicle subsystems, and analyze the virtual prototypes much like you would analyze the physical prototypes.
Using Adams/Car Ride to analyze a virtual prototype is much like requesting a test of a physical prototype. When testing in Adams/Car Ride, you specify the following:
• The virtual prototype to be tested - You specify the virtual prototype by opening or creating an assembly that contains the appropriate components, or subsystems, that make up the prototype. For example, you create a full-vehicle assembly containing suspension, steering, body, brakes, wheels, and so on.
• The kind of Analysis you'd like performed - Depends on the type of model and test rig that you have opened. You can perform analyses of components (using the component test rig), fourpost and vibration analyses (using the fourpost test rig).
• The analysis inputs to be used - You specify the inputs to the analysis by typing them directly into an analysis dialog box or by selecting a loadcase file that contains the desired inputs from an Adams/Car Ride database. Learn about Loadcase Files.
After specifying the prototype assembly and its analysis, Adams/Car Ride, like your company’s testing department, applies the inputs that you specified and records the results. To understand how your prototype behaved during the analysis, you can plot the results. After viewing the results, you can modify the prototype and analyze it again to see if your modifications improved its behavior.
Each kind of analysis that you perform requires a minimum set of subsystems. For example, a full-vehicle analysis requires front and rear suspension subsystems, front and rear wheel subsystems, one steering subsystem, and one body subsystem. Before you can create an assembly and perform an analysis in Adams/Car Ride, you must open or create the minimum set of subsystems required.
Setting up Component AnalysesYou can use a component analysis to calculate the dynamic stiffness and loss angle of a frequency-dependent bushing or damper.
To set up a component analysis:
1. From the Ride menu, point to Component Analysis, and then select Component-Model Test Rig.
2. Press F1 and then follow the instructions in the dialog box help for Component Analysis.
3. Select OK.
5Welcome to Adams/Car RideRunning Analyses
Setting up Full-Vehicle AnalysesYou can use a full-vehicle analysis to investigate a car's ride-quality characteristics.
To set up a full-vehicle analysis:
1. From the Ride menu, point to Full-Vehicle Analysis, and then select Four-Post Test Rig.
2. Press F1 and then follow the instructions in the dialog box help for Full-Vehicle Analysis: ARIDE_FOUR_POST_TESTRIG.
3. Select OK.
Setting up Full-Vehicle Vibration AnalysesYou can use a full-vehicle vibration analysis to analyze the behavior of your linearized vehicle model in the frequency domain. This includes analyses of vibration transmission frequency responses, natural frequencies, mode shapes, and damping ratios.
To set up a vibration full-vehicle analysis:
1. From the Ride menu, point to Full-Vehicle Vibration Analysis, and then select Four-Post Test Rig.
2. Press F1 and then follow the instructions in the dialog box help for Full-Vehicle Vibration Analysis: ARIDE_FOUR_POST_TESTRIG.
3. Select OK.
Controlling Analysis Output FilesYour template-based product lets you control the type and content of files an analysis outputs. You can specify whether an analysis outputs a graphics file or results file. Graphics files contain time-dependent data describing the position and orientation of each part in the model. Results files contain a basic set of state variable information that Adams/Solver calculates during a simulation.
Your template-based product automatically reads the files that an analysis outputs.
If any subsystems within the assembly being analyzed contain flexible bodies, your template-based product automatically outputs a results file, regardless of the specifications you made.
To specify analysis output files:
1. From the Settings menu, point to Solver, and then select Output Files.
The Output Files dialog box appears.
2. Select the types of files you want to output.
3. Select OK.
Adams/Car RideRunning Analyses
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Setting up Full-Vehicle A2N Analyses (MKB matrices export to Nastran)You can use a full-vehicle a2n analysis for exporting to Nastran the Mass, Stiffness and Damping matrices of your linearized vehicle model in order to provide a Modal and/or Frequency Response Analysis in the Fe code. Referring to Adams/Vibration help for full details, using Adams/Vibration – Adams2Nastran (A2N) feature, you can define the operating point at which exporting the Mass, Stiffness and Damping matrices of the full linearized model and then performing Nastran modal or frequency response analysis: the operating point has been achieved running Adams/Solver, taking into account all the nonlinearities of the system and with the possibility to easily change any parameter or variable for exploring different model configuration and, consequently, to easily recreate full Nastran equivalent model. The Mass, Stiffness and Damping matrices are exported as Nastran DMIG and connected to the system using MPC (Multi Point Constraint) while the location of input channels and output channels (Adams Markers) are exported as Nastran GRIDs and generalized degrees of freedom as SPOINTs.
The feature is limited in the sense that A2N input and output channels are automatically created, located and defined and the user can only decide actuator force values and phases, type of Nastran analysis (Modal or FRF), and how many Nastran subcases have to be created.
It has been provided an embedded and limited solution principally for showing the capability of Adams2Nastran feature. A more complete solution will be provided with the next Adams releases.
To set up a A2N full-vehicle analysis:
1. From the Ride menu, point to Full-Vehicle Vibration Analysis, and then select MKB matrices export.
2. Press F1 and then follow the instructions in the dialog box help for Full-Vehicle Vibration Analysis: MKB matrices export.
3. Select OK.
Ride Index ISO 2631-1:1997(E)It has been proven that vibration results in musculoskeletal disorders of the hand and arms, the neck and the back. There are two types of occupational vibration: segmental and whole body. Segmental vibration is transmitted through the hands and arms, while to whole body vibration (WBV) is transmitted through the body's supporting surfaces such as the legs, the back and the buttocks. Human bodies are exposed to WBV from various sources such as standing on a vibration platform, floor surface, driving, construction, manufacturing and transportation. Along with musculoskeletal problems, exposure to occupational whole body vibration also presents a health risk to the psychomotor, physiological, and psychological systems of the body.
The primary purpose here is to provide computational means for quantifying WBV as described in ISO 2631/1 procedure in relation to: human health, comfort and perception. Response to WBV depends on the frequency of vibration, acceleration (or magnitude) of vibration, number of contact points and the exposure time.
7Welcome to Adams/Car RideRunning Analyses
Frequency weighting of acceleration spectra: To calculate frequency weighted RMS acceleration, RIDE_WARMS (RIDE Weighted Acceleration RMS) function is implemented in Adams/Car Ride plug-in. This function is part of Adams expression builder and is listed under miscellaneous category. The use cases and calling syntax for health, comfort and perception are listed below.
RIDE_WARMS (ARRAY, ARRAY, ARRAY, ARRAY, ARRAY): The first real array is time or frequency sampling, second, third and fourth real arrays is acceleration signals at given location (feet, sheet or back rest) in three directions X, Y and Z respectively. The array size of these first four real arrays should be same.
The orientation of marker at given location should strictly follow the ISO guidelines for basicentric axes of the human body and the acceleration signals should be strictly passed to RIDE_WARMS in above specified order. The last character array (called Logic henceforth) is the key to select weighting curves and telling program about the domain of sampled data point (FREQ: Frequency, TIME: Time). The following example will give more insight in the function:
Example for Health:Seat Surface: Logic = {"TIME", "Wd", "Wd", "Wk"}Seat Back: Logic = {"TIME", "Wc", "Wu", "Wu"}Feet: Logic = {"TIME", "Wu", "Wu", "Wu"}
Example for Comfort:Seat Surface: x-y-z axis Logic = {"TIME", "Wd", "Wd", "Wk"}Seat Surface: rx-ry-rz axis Logic = {"TIME", "We", "We", "We"}Seat Back: Logic = {"TIME", "Wc", "Wd", "Wd"}Feet (sitting): Logic = {"TIME", "Wk", "Wk", "Wk"}Standing Vertical Recumbent (except head): Logic = {"TIME", "Wu", "Wu", "Wk"}Standing Horizontal Recumbent: Logic = {"TIME", "Wd", "Wd", "Wu"}Vertical recumbent (head): Logic = {"TIME", "Wj", "Wj", "Wj"} Vertical recumbent (head, under pelvis): Logic = {"TIME", "Wk", "Wd", "Wd"}
Example for Perception:Seat Surface: x-y-z axis Logic = {"TIME", "Wd", "Wd", "Wk"}Seat Surface: rx-ry-rz axis Logic = {"TIME", "We", "We", "We"}Seat Back: Logic = {"TIME", "Wc", "Wu", "Wu"}Standing Vertical Recumbent (except head): Logic = {"TIME", "Wu", "Wu", "Wk"}Standing Horizontal Recumbent: Logic = {"TIME", "Wd", "Wd", "Wu"}Vertical recumbent (head): Logic = {"TIME", "Wj", "Wj", "Wj"} Vertical recumbent (head, under pelvis): Logic = {"TIME", "Wk", "Wd", "Wd"}
This function returns the real array of size four. The components of this return array are: The first component of this array is weighted acceleration vector sum of signal. The next three components are simply frequency weighted RMS acceleration values in three orthogonal directions X, Y and Z. You can directly use these returned real array as input to RIDE_INDEX function as discussed below.
Combining vibrations in more than one direction:
The vibration total value (PVTV: Point Vibration Total Value and OVTV: Overall Vibration Total Value) of weighted acceleration, determined from vibration co-ordinate can be calculated using RIDE_INDEX
Adams/Car RideRunning Analyses
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function that is implemented in Adams/Car Ride plug-in. This function is part of Adams expression builder and is listed under miscellaneous category. The use cases and calling syntax for health, comfort and perception are listed below.
RIDE_INDEX (ARRAY, ARRAY, ARRAY, ARRAY, ARRAY): The first three real arrays list frequency weighted acceleration RMS values at three different locations (feet, seat and back rest) in three different directions X, Y and Z respectively. The first component of every first three array is weighted acceleration vector sum of signal. The next three components are simply frequency weighted RMS acceleration values in three orthogonal directions X, Y and Z. The array size of these first three real arrays should be four. You can directly use the return array of function RIDE_WARMS as input for these first three arrays. The fourth real array should be of size twelve and lists multiplying factors kx, ky and kz as suggested in ISO document for every location in the sequence feet, seat, back-rest and for OVTV respectively. The last string array should be of size greater than one. The RIDE_INDEX function is smart enough to return the real array of same size of this last array. The components of this last string array are listed here and you can pass them in any order you like:
MAX_WARMS: Returns maximum component value out of first three arrays MIN_WARMS: Returns minimum component value out of first three arrays PVTV_FEET: Returns vibration total value of weighted RMS acceleration at feet location PVTV_SEAT: Returns vibration total value of weighted RMS acceleration at seat location PVTV_BACK: Returns vibration total value of weighted RMS acceleration at seat back location OVTV: Returns overall vibration total value
To calculate Ride Index for Full-Vehicle Analysis:
1. From the Ride menu, point to Full-Vehicle Analysis, and then select ISO Ride index.
2. Press F1 and then follow the instructions in the dialog box help for ISO Ride Index.
3. Select OK.
To calculate Ride Index for Full-Vehicle Vibration Analysis:
1. From the Ride menu, point to Full-Vehicle Vibration Analysis, and then select ISO Ride index.
2. Press F1 and then follow the instructions in the dialog box help for ISO Ride Index.
3. Select OK.
Examples of Ride IndexExample 1 Time domain health analysis: zero contribution from X and Y direction
{a} = RIDE_WARMS(CREATE_ARRAY (0.0, 0.125, 1.0),ZEROA (9),ZEROA (9),SINA (CREATE_ARRAY (0.0, 45.0, 360.0), 1.0),
{"TIME", "Wd", "Wd", "Wk"})
9Welcome to Adams/Car RideRunning Analyses
{a} = {aVRMS, aXRMS, aYRMS, aZRMS}
Example 2Time domain health analysis by considering back-rest effect: zero contribution from feet, sine curve in Z direction and cosine curve at X and Y directions at seat.
{a} =RIDE_INDEX( RIDE_WARMS (CREATE_ARRAY (0.0, 0.125, 1.0),ZEROA (9), ZEROA (9),ZEROA (9),{"TIME", "Wu", "Wu", "Wu"}),
RIDE_WARMS (CREATE_ARRAY (0.0, 0.125, 1.0),COSA (CREATE_ARRAY(0.0,45.0,360.0),1.0),
COSA (CREATE_ARRAY(0.0,45.0,360.0),1.0),SINA (CREATE_ARRAY(0.0,45.0,360.0),1.0),{"TIME", "Wd", "Wd", "Wk"}),
RIDE_WARMS (CREATE_ARRAY (0.0, 0.125, 1.0),ZEROA (9),ZEROA (9),ZEROA (9),{"TIME", "Wc", "Wu", "Wu"}),
{1.0, 1.0, 1.0,1.4, 1.4, 1.0,1.0, 1.0, 1.0,1.0, 1.0, 1.0},
{"PVTV_SEAT"})
OR
{a} =RIDE_INDEX( RIDE_WARMS (CREATE_ARRAY (0.0, 0.125, 1.0),ZEROA (9), ZEROA (9),ZEROA (9),
{"TIME", "Wu", "Wu", "Wu"}),RIDE_WARMS (CREATE_ARRAY (0.0, 0.125, 1.0),
COSA (CREATE_ARRAY(0.0,45.0,360.0),1.0),COSA (CREATE_ARRAY(0.0,45.0,360.0),1.0),SINA (CREATE_ARRAY(0.0,45.0,360.0),1.0),{"TIME", "Wd", "Wd", "Wk"}),
RIDE_WARMS (CREATE_ARRAY (0.0, 0.125, 1.0),ZEROA (9),ZEROA (9),ZEROA (9),{"TIME", "Wc", "Wu", "Wu"}),
Adams/Car RideRunning Analyses
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{1.0, 1.0, 1.0,1.4, 1.4, 1.0,1.0, 1.0, 1.0,1.0, 1.0, 1.0},{"PVTV_SEAT", "PVTV_SEAT", "PVTV_FEET",
"MAX_WARMS", "MIN_WARMS", "OVTV"})
Example 3Other useful functions to create 1/3 octave frequencies and validate ISO weighting curves
{fc} = POWA (CREATE_ARRAY (-17/3, 1/3, 26/3), 2.0) OR
{fc} = POWA (CREATE_ARRAY (-17, 1, 26), 2.0^ (1/3))
{Wk} = RIDE_WEIGHTING ({fc},"Wk")
{Wd} = RIDE_WEIGHTING ({fc},"Wd")
Remarks:
1. You can pass SPLINES for experimental data and/or arrays form simulation that you get after four-post simulation of full vehicle assembly.
2. The data passed to these functions must be in MKS units
3. The OVTV for translation and rotation should be calculated separately.
11Welcome to Adams/Car RideExamples of Using Adams/Car Ride
Examples of Using Adams/Car RideThe following Adams/Car Ride examples are available:
• Getting Started Using Adams/Car Ride
• Example Input Hydromount Property File
• Example Output Hydromount Property File
• Example Input Bushing Property File
• Example Output Bushing Property File
Adams/Car RideExamples of Using Adams/Car Ride
12
Working with Components
Adams/Car RideGeneral Frequency-Dependent Element
14
General Frequency-Dependent Element
Component Name
ac_general_f_d_element
Source Directory
/$MDI_RIDE_PLUGIN/template_builder/udes/ac_general_f_d_element
Description
This component is a six degrees-of-freedom force, having each component modeled by three linear springs and three linear dampers; the elements of the single component can be connected in different ways and eventually deactivated to create the following:
1. Linear Pfeffer element (one spring in parallel with a series damper - parallel spring damper)
2. Simple FD damper (one spring in parallel with a series spring damper)
3. Simple FD bushing (one spring in series with a parallel spring damper)
4. General element (one parallel spring damper in parallel with a series of two parallel spring dampers)
You can also specify a preload for each force component.
Using the replace feature in Standard Interface, you can create a general frequency-dependent element as a replacement for a standard Adams/Car bushing. In the replacement element dialog box, select a property file, setting preload, and activity for each component.
Specifications
.ARIDE.forcess.ac_general_f_d_element
Parameters
Parameter: Type: Function:
property_file string variable Name of property file
X_type string variable X component element type
T_preload_x real variable Element translational preload x
X_C1 real variable
X_K1 real variable
X_C2 real variable
X_K2 real variable
X_C3 real variable
15Working with ComponentsGeneral Frequency-Dependent Element
X_K3 real variable
Y_type string variable Y component element type
T_preload_y real variable Element translational preload y
Y_C1 real variable
Y_K1 real variable
Y_C2 real variable
Y_K2 real variable
Y_C3 real variable
Y_K3 real variable
Z_type string variable Z component element type
T_preload_z real variable Element translational preload z
Z_C1 real variable
Z_K1 real variable
Z_C2 real variable
Z_K2 real variable
Z_C3 real variable
Z_K3 real variable
AX_type string variable AX component element type
R_preload_x real variable Element rotational preload x
AX_C1 real variable
AX_K1 real variable
AX_C2 real variable
AX_K2 real variable
AX_C3 real variable
AX_K3 real variable
AY_type string variable AY component element type
R_preload_y real variable Element rotational preload y
AY_C1 real variable
AY_K1 real variable
AY_C2 real variable
AY_K2 real variable
AY_C3 real variable
AY_K3 real variable
Parameter: Type: Function:
Adams/Car RideGeneral Frequency-Dependent Element
16
Input Parameters
Output Parameters
none
Objects:
AZ_type string variable AZ component element type
R_preload_z real variable Element rotational preload z
AZ_C1 real variable
AZ_K1 real variable
AZ_C2 real variable
AZ_K2 real variable
AZ_C3 real variable
AZ_K3 real variable
X_active integer variable
Y_active integer variable
Z_active integer variable
AX_active integer variable
AY_active integer variable
AZ_active integer variable
I_geo_marker object variable
J_geo_marker object variable
geo_radius real variable
geo_length real variable
Bushing_jfloat object variable
Input parameter: Type: Function:
i_marker object variable Action marker
j_marker object variable Reaction marker
Object: Type:
Force single_component_force
Gse general_state_equation
Parameter: Type: Function:
17Working with ComponentsGeneral Frequency-Dependent Element
Request Definition
disp_request
U_var_x state variable
U_var_y state variable
U_var_z state variable
U_var_ax state variable
U_var_ay state variable
U_var_az state variable
State_array X_state_array
Output_array Y_output_array
Ic_array IC_array
Input_array U_input_array
KC_array IC_array
Disp_Request request
Velo_Request request
Acc_Request request
Force_Request request
Component name: Component units: Definition:
DX Length Distance between i_marker and j_marker along j_marker X
DY Length Distance between i_marker and j_marker along j_marker Y
DZ Length Distance between i_marker and j_marker along j_marker Z
AX Angle Angle between i_marker and j_marker X
AY Angle Angle between i_marker and j_marker Y
AZ Angle Angle between i_marker and j_marker Z
Object: Type:
Adams/Car RideGeneral Frequency-Dependent Element
18
velo_request
acc_request
Component name: Component units: Definition:
VX Velocity Relative velocity between i_marker and j_marker along j_marker X
VY Velocity Relative velocity between i_marker and j_marker along j_markerY
VZ Velocity Relative velocity between i_marker and j_marker along j_marker Z
WX Angular Velocity Relative angular velocity between i_marker and j_marker X
WY Angular Velocity Relative angular velocity between i_marker and j_marker Y
WZ Angular Velocity Relative angular velocity between i_marker and j_marker Z
Component name: Component units: Definition:
AX Acceleration Relative acceleration between i_marker and j_marker along j_marker X
AY Acceleration Relative acceleration between i_marker and j_marker along j_marker Y
AZ Acceleration Relative acceleration between i_marker and j_marker along j_marker Z
WDTX Angular Acceleration Relative angular acceleration between i_marker and j_marker X
WDTY Angular Acceleration Relative angular acceleration between i_marker and j_marker Y
WDTZ Angular Acceleration Relative angular acceleration between i_marker and j_marker Z
19Working with ComponentsGeneral Frequency-Dependent Element
force_request
Design Parameters
Macros
Create Macro: (call: acar template_builder instance ac_general_f_d_element create) Adams/Car Ride executes this macro when you create an instance of the definition ac_general_f_d_element.
Modify Macro: (call: acar template_builder instance ac_general_f_d_element modify) Adams/Car Ride executes this macro when you modify an instance of the definition ac_general_f_d_element.
Component name: Component units: Definition:
FX Force Force between i_marker and j_marker along j_marker X
FY Force Force between i_marker and j_marker along j_marker Y
FZ Force Force between i_marker and j_marker along j_marker Z
TX Torque Torque between i_marker and j_marker X
TY Torque Torque between i_marker and j_marker Y
TZ Torque Torque between i_marker and j_marker Z
Parameter: Type: Function:
scaling_factor real variable Scaling factor (DOE)
Adams/Car RideSingle Component Frequency-Dependent Elements
20
Single Component Frequency-Dependent Elements
Component Name
ac_single_f_d_element
Source Directory
/$MDI_RIDE_PLUGIN/template_builder/udes/ac_single_f_d_element
Description
This component is a one degree of freedom force modeled by three linear springs and three linear dampers; the elements may be connected in different ways and eventually deactivated in order to create the following:
1. Linear Pfeffer element (one spring in parallel with a series damper - parallel spring damper)
2. Simple FD damper (one spring in parallel with a series spring damper)
3. Simple FD bushing (one spring in series with a parallel spring damper)
4. General element (one parallel spring damper in parallel with a series of two parallel spring dampers)
Using the replace feature in Standard Interface, you can create a general frequency-dependent element as a replacement for a standard Adams/Car bushing. In the replacement element dialog box, select a property file and setting preload for the component.
Specifications
.ARIDE.forcess.ac_single_f_d_element
Parameters
Parameter: Type: Function:
property_file string variable Name of property file
preload real variable Element preload
type string variable Element type
scale_factor real variable Force scale factor
geo_scale real variable Geometry scale
21Working with ComponentsSingle Component Frequency-Dependent Elements
Input Parameters
Output Parameters
none
Objects:
Input parameter: Type: Function:
i_marker object variable Action marker
j_marker object variable Reaction marker
Object: Type:
C1 real variable
K1 real variable
C2 real variable
K2 real variable
C3 real variable
K3 real variable
F01 real variable
F03 real variable
Uvar state variable
Outvark1c1 state variable
State_array X_state_array
Output_array Y_output_array
Ic_array IC_array
Input_array U_input_array
Force single_component_force
Gse general_state_equation
Request request
Graphic geometry
Dm_calc real variable
Adams/Car RideSingle Component Frequency-Dependent Elements
22
Request Definition
request
user (904,i_marker,j_marker)
Design Parameters
Macros
Create Macro: (call: acar template_builder instance ac_single_f_d_element create) Adams/Car Ride executes this macro when you create an instance of the definition ac_single_f_d_element.
Modify Macro: (call: acar template_builder instance ac_single_f_d_element modify) Adams/Car Ride executes this macro when you modify an instance of the definition ac_single_f_d_element.
Component name: Component units: Definition:
Displacement length Distance between i_marker and j_marker
Velocity velocity Relative velocity of i_marker and j_marker
Force force Force between i_marker and j_marker
Parameter: Type: Function:
scaling_factor real variable Scaling factor (DOE)
23Working with ComponentsFrequency Bushing
Frequency Bushing
Component Name
ac_frequency_bushing
Source Directory
/$MDI_RIDE_PLUGIN/template_builder/udes/ac_frequency_bushing
Description
This component is based on a GFORCE element. The damping coefficients of the GFORCE are interpreted as the loss angles. The forces in the x- and y-plane and the moments along the x- and y-axis are interpolated elliptical. The z force and moment are mapped directly from the splines.
Specifications
.ARIDE.parts.ac_frequency_bushing
Parameters
Parameter: Type: Function:
property_file string variable name of property file
t_preload_x real variable translational preload
t_preload_y real variable translational preload
t_preload_z real variable translational preload
r_preload_x real variable rotational preload
r_preload_y real variable rotational preload
r_preload_z real variable rotational preload
t_offset_x real variable translational offset
t_offset_y real variable translational offset
t_offset_z real variable translational offset
r_offset_x real variable rotational offset
r_offset_y real variable rotational offset
r_offset_z real variable rotational offset
i_geoMarker marker geometry ref marker
j_geoMarker marker geometry ref marker
geoRadius real variable geometry radius
geoLength real variable geometry length
Adams/Car RideFrequency Bushing
24
Input Parameters
Output Parameters
none
Objects
Request Definition
disp_request
user (0,1,i_marker,j_marker,gforce)
Input parameter: Type: Function:
i_marker object variable action marker
j_marker object variable marker whose parent is the reaction part and reference marker
Object: Type: Function:
data_array Adams array array to pass the preloads, offsets, damping coefficients to the field subroutine
fx_spline Adams spline force spline
fy_spline Adams spline
fz_spline Adams spline
tx_spline Adams spline torque spline
ty_spline Adams spline
tz_spline Adams spline
i_graphic revolution graphics on I part
j_graphic cylinder graphics on J part
disp_request request displacement request subroutine ROUTINE = aride_solver::reqaride
velo_request request velocity request subroutine ROUTINE = aride_solver::reqaride
force_request request force request subroutine ROUTINE = aride_solver::reqaride
gforce gforce frequency dependent bushing gforce subroutine as part of the plugin ride_solver::FREQUENCY_BUS
Component name: Component units: Definition:
dx length x-distance between i_marker and j_marker
dy length y-distance between i_marker and j_marker
25Working with ComponentsFrequency Bushing
velo_request
user (0,2,i_marker,j_marker,gforce)
force_request
user (0,6,i_marker,j_marker,gforce)
dz length z-distance between i_marker and j_marker
dm length magnitude
ax angle angle about x
ay angle angle about y
az angle angle about z
amag angle magnitude
Component name: Component units: Definition:
vx velocity x-velocity between i_marker and j_marker
vy velocity y-velocity between i_marker and j_marker
vz velocity z-velocity between i_marker and j_marker
vm velocity magnitude
wx angular_velocity
wy angular_velocity
wz angular_velocity
wm angular_velocity magnitude
Component name: Component units: Definition:
bushing_fx force x-force between i_marker and j_marker
bushing_fy force y-force between i_marker and j_marker
bushing_fz force z-force between i_marker and j_marker
fm force magnitude
bushing_tx torque
bushing_ty torque
bushing_tz torque
tm torque magnitude
Component name: Component units: Definition:
Adams/Car RideFrequency Bushing
26
Subsystem Parameters
Design Parameters
Macros
Create Macro: (call: acar template_builder instance ac_frequency_bushing create) Adams/Car Ride executes this macro when you create an instance of the definition ac_frequency_bushing.
Modify Macro: (call: acar template_builder instance ac_frequency_bushing modify) Adams/Car Ride executes this macro when you modify an instance of the definition ac_frequency_bushing.
Delete Macro: (call: acar template_builder instance ac_frequency_bushing delete) This macro deletes all the entities which have been created exclusively for the instance.
See About the Bushing Model for more information.
Top level: Sub level:
property_file
t_preload_(x-z)
r_preload_(x-z)
t_offset_(x-z)
r_offset_(x-z)
Parameter: Type: Function:
fx_scaling_factor real variable scaling factor (DOE)
fy_scaling_factor real variable scaling factor (DOE)
fz_scaling_factor real variable scaling factor (DOE)
tx_scaling_factor real variable scaling factor (DOE)
ty_scaling_factor real variable scaling factor (DOE)
tz_scaling_factor real variable scaling factor (DOE)
27Working with ComponentsGeneral Bushing
General Bushing
Component Name
ac_general_bushing
Source Directory
/$MDI_RIDE_PLUGIN/template_builder/udes/ac_general_bushing
Description
This component is based on a GFORCE element such as the standard ac_bushing. The forces in all six directions are orthogonal or can be coupled in rectangular, cylindrical or spherical ways. The total force from this element is sum of preload, static spline force, TFSISO force, Bouc-wen hysteresis force and viscous damping force.
Specifications
.ARIDE.parts.ac_general_bushing
Parameters
Parameter: Type: Function:
property_file string variable name of property file
t_preload_x real variable translational preload
t_preload_y real variable translational preload
t_preload_z real variable translational preload
r_preload_x real variable rotational preload
r_preload_y real variable rotational preload
r_preload_z real variable rotational preload
t_offset_x real variable translational offset
t_offset_y real variable translational offset
t_offset_z real variable translational offset
r_offset_x real variable rotational offset
r_offset_y real variable rotational offset
r_offset_z real variable rotational offset
i_geoMarker marker geometry ref marker
j_geoMarker marker geometry ref marker
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Input Parameters
Output Parameters
none
Objects
geoRadius real variable geometry radius
geoLength real variable geometry length
Input parameter: Type: Function:
i_marker object variable action marker
j_marker object variable marker whose parent is the reaction part and reference marker
Object: Type: Function:
bushing_shape integer value 1: rectangular coupling
2: cylindrical coupling
3: spherical coupling
gen_coupling integer value 0: Uncouple Bouc-wen force from linear stiffness force
1: Couple Bouc-wen force with linear stiffness force
(tx-rz)_data_array Adams array array to pass stiffness and damping types, scales, spline ID, preload, damping and velocity offsets and scales, static spline ID, Bouc-wen parameters ALPHA, ZETA, OMEGA, K, hysteresis type, hysteresis spline ID/Bouc-wen DIFF ID, hysteresis/Bouc-wen force scale, TFSISO output array ID and TFSISO force scale to the subroutine
data_array_(x-az) Adams array array to pass the Bouc-wen model parameters BETA, GAMMA, A and N to the subroutine
(x-az)_alpha real variable Bouc-wen parameter
(x-az)_beta real variable Bouc-wen parameter
(x-az)_gamma real variable Bouc-wen parameter
(x-az)_zeta real variable Bouc-wen parameter
Parameter: Type: Function:
29Working with ComponentsGeneral Bushing
Request Definition
disp_request
user (905,1,i_marker,j_marker,field) and routine = aride_solver::reqaride
(x-az)_omega real variable Bouc-wen parameter
(x-az)_a real variable Bouc-wen parameter
(x-az)_n real variable Bouc-wen parameter
(x-az)_num real variable TFSISO NUM array
(x-az)_den real variable TFSISO NUM array
fx_spline Adams spline force spline
fy_spline Adams spline
fz_spline Adams spline
tx_spline Adams spline torque spline
ty_spline Adams spline
tz_spline Adams spline
i_graphic revolution graphics on I part
j_graphic cylinder graphics on J part
disp_request request displacement request
velo_request request velocity request
force_request request force request
gforce gforce bushing dependent bushing gforce subroutine as part of the AvSub::FD_BUSHING
Component name: Component units: Definition:
dx length x-distance between i_marker and j_marker
dy length y-distance between i_marker and j_marker
dz length z-distance between i_marker and j_marker
dm length magnitude
ax angle angle about x
ay angle angle about y
az angle angle about z
amag angle magnitude
Object: Type: Function:
Adams/Car RideGeneral Bushing
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velo_request
user (905,2,i_marker,j_marker,field) and routine = aride_solver::reqaride
force_request
user (905,3,i_marker,j_marker,field) and routine = aride_solver::reqaride
Subsystem Parameters
Component name: Component units: Definition:
vx velocity x-velocity between i_marker and j_marker
vy velocity y-velocity between i_marker and j_marker
vz velocity z-velocity between i_marker and j_marker
vm velocity magnitude
wx angular_velocity
wy angular_velocity
wz angular_velocity
wm angular_velocity magnitude
Component name: Component units: Definition:
bushing_fx force x-force between i_marker and j_marker
bushing_fy force y-force between i_marker and j_marker
bushing_fz force z-force between i_marker and j_marker
fm force magnitude
bushing_tx torque
bushing_ty torque
bushing_tz torque
tm torque magnitude
Top level: Sub level:
property_file
t_preload_(x-z)
r_preload_(x-z)
t_offset_(x-z)
r_offset_(x-z)
31Working with ComponentsGeneral Bushing
Design Parameters
Macros
Create Macro: (call: acar template_builder instance ac_general_bushing create) Adams/Car Ride executes this macro when you create an instance of the definition ac_general_bushing.
Modify Macro: (call: acar template_builder instance ac_general_bushing modify) Adams/Car Ride executes this macro when you modify an instance of the definition ac_general_bushing.
Delete Macro: (call: acar template_builder instance ac_general_bushing delete) This macro deletes all the entities which have been created exclusively for the instance.
About Input Bushing Property FilesThe block [MDI_HEADER] must be exactly the same as in the Example Input Bushing Property File.
In the block [UNITS] you could specify the units your test data is in.
The block [GENERAL] must contain all parameters listed in the sample file. The details of each parameters and its meaning is given IPIT help.
• The DEFINITION is always '.aride.attachment.ac_general_bushing'
• The BUSHING_COORDINATE can be x, y, z, ax, ay, az or g. This parameter determines the co-ordinate in which the bushing parameters will be identified. The co-ordinate 'g' should be used to identify user defined bushing. Please refer to gen_bus002.gbu under shared Aride database for further information.
• BUSHING_SHAPE = 0 or 1 or 2 or 3. 0 or 1: rectangular coupling, 2: cylindrical coupling, 3: spherical coupling. All these types are supported in Adams/Car Models. IPIT uses only rectangular coupling during identification.
• BUSHING_COUPLING = 0 (un-coupled bushing force) or 1 (coupled bushing force). Please refer to bushing help for coupled and uncoupled bushing force.
The blocks [DAMPING], [PRELOAD], [OFFSET], [SPLINE_SCALES], [HYST_SCALES] and [TFSISO_SCALES] are optional. Please see bushing help for their default values and further information.
Parameter: Type: Function:
fx_scaling_factor real variable scaling factor (DOE)
fy_scaling_factor real variable scaling factor (DOE)
fz_scaling_factor real variable scaling factor (DOE)
tx_scaling_factor real variable scaling factor (DOE)
ty_scaling_factor real variable scaling factor (DOE)
tz_scaling_factor real variable scaling factor (DOE)
Adams/Car RideGeneral Bushing
32
The Blocks [FX_CURVE], [FY_CURVE], [FZ_CURVE], [TX_CURVE], [TY_CURVE], [TZ_CURVE] are given to supply static splines. Spline in your bushing co-ordinate direction is compulsory, others are optional. For example, if your bushing co-ordinate is 'z', you must supply [FZ_CURVE].
The [BUSHING_PARAMETERS] block is basically to supply bushing parameters values. While using in Adams/Car Assembly and IPIT, your bushing force is calculated using these parameters. The IPIT updates these data as it progress over identification. If your bushing co-ordinate is x/y/z/ax/ay or az then, you should supply Bouc-wen and TFSISO parameters.If your bushing co-ordinate is 'g', then you should directly supply your variable initial values and there lower and upper bound limits. Please see gen_bus002.gbu for example use of 'g' co-ordinate. Please note that the co-ordinate 'g' is meant to IPIT only and it does not have any meaning in Adams/Car Assembly. This co-ordinate is very helpful if you want to identify user bushing is any.
The block [BUSHING_TEST_DATA] contains four columns of data. These are the measured data of the bushing. For every amplitude you must have the same frequencies. The number of amplitudes is not fixed. You could also use a property file including the bushing parameters, which you can edit manually, or use a file that was written by a previous identification process. This allows you to first use rather larger error tolerances to speed up the process with relatively rough results before you run the identification process using those results as initial values with a smaller error tolerance. Or you could add additional test data later and redo the identification based on previously identified parameters
The block [BUSHING_SCALE_DATA] contains four columns of data as well. These are the scales IPIT will use while calculating objection function. This is optional block, the defaults cdyn and phase scales are unity for all amplitudes and frequencies. If, you do not supply these block, IPIT will give you message that it is creating unity scale data.
The block [BUSHING_IDENTIFICATION_DATA] contains four columns of data as well. These are the identified dynamic stiffness and phase data. This is optional block, the calculated cdyn and phase data is entered there by IPIT.
See Example Input Bushing Property File.
See Example Output Bushing Property File.
33Working with ComponentsGSE Damper
GSE DamperTo use a GSE damper, you must have a license for Adams/Controls.
Adams's system modeling elements enable the modeling and importing of external dynamic systems. Those elements make it possible for users to define transfer functions, linear state equations, and nonlinear state equations outside of Adams, and then input them for use with Adams. Among those, the general state equation (GSE) is designed to model and import nonlinear external dynamic systems, such as a damper.
The GSE damper provided with Adams/Car Ride illustrates a simple ride-based damper that has been
created within Mathworks® Simulink® and exported using Mathworks RealTime Workshop® (RTW). The GSE damper provides a framework that you can use to import proprietary damper models into Adams/Car Ride.
For more information on importing the object code of the damper, see the guide, Getting Started Using Adams/Controls.
Learn more about GSE dampers:• Scope
• Results
• Parametric Studies
• Solver Background
• Benefits of External Dynamic System Import
Scope
Provided with Adams/Car Ride is a complete set of files that you can use with Mathworks Simulink and Adams/Car Ride to incorporate and test the functionality of the GSE damper. A license of Mathworks Simulink and appropriate compilers is required to carry out this process. If, however, another user provides you with a library (.dll, .so, or .sl, depending on your platform), you will only need a license of Adams/Controls and Adams/Car Ride to run an analysis within Adams.
This topic provides a guide to using the GSE damper component. It does not explain how to use Mathworks Simulink or how to export a library using RTW.
Results
When you create a GSE damper, Adams/Car Ride automatically creates some associated REQUEST statements. These requests measure the displacement, velocity, and force across the damper.
Parametric Studies
As with all elements, in Adams/Car Ride you can study the parametric behavior of components. You can modify a number of parameters for use in Adams/Insight. The parameter data is stored in the corresponding subsystem file.
Adams/Car RideGSE Damper
34
Solver Background
A General State Equation (GSE) is an Adams element designed for time-variant, nonlinear, continuous or discrete dynamic systems, which can be mathematically represented as follows:
(1)
(2)
(3)
....
The definition of GSEs contains two portions:
• GSE statement in the model: Provides the interface with Adams model, and specifies the attributes of the imported dynamic system.
• GSE library: A library of code written to the Adams GSE specification. For more information on general state equations, see the online help for Adams/Solver.
Benefits of External Dynamic System Import
Embedding external dynamic systems into Adams allows the use of a unified platform for multi-domain analyses, and provides the following advantages over a cosimulation-based approach:
• Faster speed: Powerful Adams integrators can simulate the stiff combined systems at a speed unmatched by function-evaluation mode in Adams/Controls.
• Higher accuracy: Because the external dynamic systems and the Adams model are incorporated into one formulation, the dynamic coupling between them can be precisely represented, and its effect is taken into account during the simulation. The accuracy achieved with external dynamic systems imported is unparalleled compared to those from cosimulation and function-evaluation mode.
• DOE with Adams/Insight
• Protecting proprietary code: Because the external dynamic systems can be imported in the form of an object file and demand-loaded library, the proprietary code is not exposed.
However, to create both the GSE statement and the demand-load library manually, you need a high level of programming skills and a deep understanding of Adams/Solver. To facilitate the creation of the GSE, an external system import utility is designed as a feature of the GSE damper element to import the external dynamic systems code.
xc·
fc xc u t = xc t0 xc0=
xdn 1+fd xdn
u t = xd t0 xd0=
y g xc xd u t =
35Working with ComponentsGSE Damper
Control System Import
The Control System Import performs the following steps:
1. Creates a library.
2. Queries the library to be imported for the information used to update the GSE statement of the GSE damper element. The external dynamic system library should provide information, such as number of states, inputs and outputs, and the tunable parameter.
3. Performs an error check to ensure that the external system complies with the standard required by the GSE damper element.
4. Generates a property file in the default writable database, which contains the parameters of your Simulink model.
During the simulation, the demand-loaded library is loaded into and called by Adams/Solver to provide derivatives of states and output for Adams/Solver to integrate.
A set of example files is located in the shared_ride_database.cdb/gse_damper.tbl.
Simulink Damper ModelThis section teaches you how to generate an External System Library (ESL) for a damper designed in MATLAB/Simulink and import them into Adams/Car Ride. Adams/Controls is required to use this feature, and uses a similar, but more generalized process of Control System Import. Please refer Adams/Controls for further details of the general method of importing models from Simulink or Easy5.
A Simulink damper model can be used when you want to model proprietary dampers in Adams. Due to the customized process in Adams/Car Ride, the damper model must have three inputs, in the following order:
• Displacement
• Velocity
• Acceleration between the markers I and J.
Inputs not required by the Simulink model must be terminated with a terminator block. The model must have one output, which is the force from the Simulink modal of the damper to be applied in the Adams model. The inputs and output are in Adams modeling units. The sample Simulink file damper_example_tf.mdl is provided in Aride shared database under gse_damper.tbl folder for demonstration.
Following are the basic steps one has to perform to use Simulink damper in Adams:
• Step One - Replace Damper with GSE_Damper
• Step Two - Export the Plant File for MATLAB
• Step Three - Setup MATLAB
• Step Four - Create Adams Target for Real Time Workshop
Adams/Car RideGSE Damper
36
• Step Five - Create Simulink Model
• Step Six -Code Generation of Simulink Damper Model (Control System)
• Step Seven - Select the Damper Library and Simulate
Step One - Replace Damper with GSE_Damper
First you will start Adams/Car and open component test rig, and then perform a Replace operation to create a GSE_Damper.
To start Adams/Car and open component test rig:
1. Launch Adams/Car
2. Load the Adams/Car Ride plug-in, if not already loaded and open the assembly: component_damper_example.asy
3. Use Replace feature in Aride to replace Damper with GSE_damper
(Right click the assembly and select Damper:component_damper_001.das_dar_ride_damper -> Replace)
This is required to create the input and output state variables for the damper model in Simulink
Step Two - Export the Plant File for MATLAB
In this section, you will export the Adams linear and nonlinear plant files to MATLAB.
1. Click the to launch the Adams/Controls Plant Export dialog box.
37Working with ComponentsGSE Damper
2. Complete the dialog box as shown below.
3. Click OK
Adams/Controls save the input and output information in a gse_damper.m file under working directory
Step Three - Setup MATLAB
First you will start MATLAB, and then you will create a Simulink model for control system design. You will use the Plant Export.m file to setup MATLAB, as well as the example_damper_tf model files supplied in Aride shared database,
To start MATLAB:
1. Start MATLAB in the same directory as on the model and Simulink files reside.
2. Set up the MEX utility, if not already set.
Enter mex -setup from the MATLAB command window, and then select the appropriate compiler. (see http://support.adams.com under Hardware & Software Requirements for a list of supported compilers)
3. At the prompt (>>), enter gse_damper
MATLAB displays the following:
%%% INFO : ADAMS plant actuators names :1 force_state%%% INFO : ADAMS plant sensors names :1 displacement_state2 velocity_state 3 acceleration_state
4. At the prompt, enter who to view the list of variables defined in the files.
MATLAB displays the following relevant information:
ADAMS_cwd ADAMS_pinput ans ADAMS_exec ADAMS_poutput arch ADAMS_host ADAMS_prefix flag ADAMS_init ADAMS_solver_type machine ADAMS_inputs ADAMS_static temp_str
Adams/Car RideGSE Damper
38
ADAMS_mode ADAMS_sysdir topdir ADAMS_outputs ADAMS_uy_ids
You can check any of the above variables by entering them at the MATLAB prompt. For example, if you enter Adams_outputs, MATLAB displays all of the outputs defined for your mechanism, that is: ADAMS_outputs = displacement_state!velocity_state!acceleration_state.
Step Four - Create Adams Target for Real Time Workshop
In order to generate the External System Library from the MATLAB/Simulink model, you need to generate some special files for MATLAB/Real-Time Workshop (RTW). You will customize the Makefile template and source code template for Adams, based on the version of MATLAB. Once this is done, you can use the customized template files for other Simulink models.
To create the Real-Time Workshop files for the Adams/Controls model:
1. At the MATLAB prompt (>>), enter setup_rtw_for_adams
This will automatically detect the version of Matlab you are using and then create the makefile template, source code template for Adams. This function will also build template for specific versions of Matlab if desired by entering the desired version token as an argument: setup_rtw_for_adams('<version>')). For help on this, enter setup_rtw_for_adams('h').
You should see the following message for success in this step:
%%% Successfully created files for Adams library export from MATLAB/RTW.
You should also confirm that in your working directory that .tlc and .tmf files were created by this step.
Alternatively, since the function setup_rtw_for_adams also uses process.py, you can still setup using the old method:
(Optional method if not using setup_rtw_for_adams function)
a. Set the MATLAB_ROOT environment variable to the MATLAB installation directory. For example:
• On Windows (DOS shell): set MATLAB_ROOT= c:\matlab78\
• On UNIX (c shell): setenv MATLAB_ROOT /usr/matlab_78/
• On UNIX (korn shell): export MATLAB_ROOT = /usr/matlab_78/
• Change the directory paths to match your installation.
b. In the directory where your Adams model resides, enter the following command, where $adams_dir is the directory in which Adams is installed:
• On UNIX: mdadams2010 -c python ($adams_dir)/controls/utils/process.py -v 78 exit
• On Windows: mdadams2010 python ($adams_dir)\controls\utils\process.py -v 78
Alternatively, you can copy the process.py file from the <adams_dir>/controls/utils/ directory on UNIX or <adams_dir>\controls\utils\ on Windows to the current directory and issue the following command:
• On UNIX: mdadams2010 -c python process.py -v 78 exit
39Working with ComponentsGSE Damper
• On Windows: mdadams2010 python process.py -v 78
The argument -v 78 stands for MATLAB 7.8 (R2009a).
This command customizes several files from the MATLAB installation for the Adams target and your computer setup. You should notice several new files in your working directory with a .tlc extension and two new files with a .tmf extension. These files required by MATLAB's Real Time Workshop in the steps that follow. For help with process.py, use the -h flag (that is, process.py -h).
Step Five - Create Simulink Model
To create the Simulink template for the control system:
1. Enter setio at the MATLAB prompt.
MATLAB creates a template model with the inport(s) and outport(s) defined, as shown below.
Based on this template, you can design your proprietary damping systems. These files you already copied into the local directory.
Note: The value for MATLAB_ROOT should have no quote, no spaces (on Windows, get short names with command dir /x), and a final slash on the path. For example, if you want to set C:\Program Files\matlab78\ as your MATLAB_ROOT, then do it as: set MATLAB_ROOT= C:\PROGRA~1\matlab78\
Adams/Car RideGSE Damper
40
2. Rather creating a new model, use the example found in the Adams/Car Ride shared database (<aride_shared>/gse_dampers.tbl/damper_example_tf.mdl). To open damper_example_tf.mdl, from the File menu, select Open. Or, double-click the file in the file browser.
In the following context, the damper control system will be used as the example to illustrate the process. Following figure shows the damper Simulink model provided and its associated plant input and outputs.
Step Six -Code Generation of Simulink Damper Model (Control System)
First you will configure MATLAB/Real-Time Workshop and then you will create the External System Library from the Simulink model. Given a controller designed with the appropriately designated inports and outports, the following steps are required to export the model using RTW.
1. From the Tools menu, point to Real-Time Workshop, and then select Options.
The Simulation Parameters dialog box appears.
2. Verify Generate code only option is not selected.
3. Select Browse next to System target file and choose the rsim.tlc target.
The completed Simulink Parameters dialog box should look as shown below.
41Working with ComponentsGSE Damper
4. From the treeview on the left side of the window, select Solver.
The dialog box displays the Solver options as shown below
Adams/Car RideGSE Damper
42
5. Set Solver options Type to Variable-Step. (If selecting Fixed-Step solver, set Mode to SingleTasking.)
6. Under zero-crossing options, set Zero-crossing to Disable All.
The completed Simulink Parameters dialog box should look as shown below.
7. From the treeview on the left side of the window, select Optimization.
The dialog box displays the Advanced options as shown in below figure.
43Working with ComponentsGSE Damper
8. Verify Inline parameters options is selected. Enabling Inline parameters has the following effects:
• Real-Time Workshop uses the numerical values of model parameters, instead of their symbolic names, in generated code.
• Reduces global RAM usage, because parameters are not declared in the global parameters structure.
9. Select "Configure…" button to open the Model Parameters Configuration dialog box and verify that parameters ReboundDamping and CompressionDamping are selected as Global (tunable) parameters. This will allow Adams to create design variables for these parameters.
Adams/Car RideGSE Damper
44
10. Select OK to close the Model Parameters Configuration dialog box.
45Working with ComponentsGSE Damper
11. Click Apply.
12. Define the parameters in MATLAB workspace by issuing the following
ReboundDamping = 100;
CompressionDamping = 200;
(You can access the two MATLAB variables from the Simulink model by double-clicking them.)
Adams/Car RideGSE Damper
46
13. Select the Real-Time Workshop tab
14. To begin code generation and build the RTW library, select Build
47Working with ComponentsGSE Damper
Messages will appear in the MATLAB command window indicating successful code generation and RTW library creation. You should see messages that end with the following:
Creating library ..\damper_example_tf.lib and object ..\damper_example_tf.exp "### Created Adams External System Library damper_example_tf.dll" E:\tmp\gse_damper\damper_example_tf_rsim_rtw>exit /B 0 ### Successful completion of Real-Time Workshop build procedure for model: damper_example_tfThe library you created will be in your working directory.
Step Seven - Select the Damper Library and Simulate
First you will start Adams/Car and open component test rig, and then simulate your Adams model containing the GSE for the control system.
To start Adams/Car and import External System Library (ESL):
1. If you haven't already done then launch Adams/Car
2. Load the Adams/Car Ride plug-in, if not already loaded and open the assembly: component_damper_example.asy
3. Use Replace feature in Aride to replace Damper with GSE_damper
(Right click the assembly and select Damper:component_damper_001.das_dar_ride_damper -> Replace)
Adams/Car RideGSE Damper
48
4. Click OK. This will launch the Modify GSE Damper dialog box. If not, Right Click Damper: component_damper_001.das_dar_ride_damper and select Modify
5. Click the to import the External System Library (ESL) for the damper. This will launch a GSE Damper Code Import dialog box.
6. Right-click the Library to be imported field, and select Browse. Choose damper_example_tf.[dll,so]
7. Click the Property file name field and enter "damper_example_tf"
This will create a properly file for the ESL and will automatically update the Property File filed of Modify GSE Damper dialog to point it.
To run simulation and plot GSE_damper force:
1. From the Ride menu, point to Component Analysis, and then select Component-Model Test Rig …
The Adams/Car Ride Component Analysis dialog box appears.
(Please refer Aride Component Analysis help to do Component Analysis.)
49Working with ComponentsGSE Damper
2. Plot the force from GSE damper force in Adams/Post Processor
Adams/Car RideHydromounts
50
Hydromounts
Component Name
ac_hydro_bushing
Source Directory
/$MDI_RIDE_PLUGIN/template_builder/udes/hydro_bushing
Description
This component is based on the Weber model, which consists of a hydro path, a parallel spring, and a parallel damper.
Nonlinear Model
The nonlinear model consists of up to eight parameters:
• CouplingStiffness
• RubberStiffness
• LinearFluidDamping
• RubberDamping
• EffectiveFluidMass
• CouplingStiffnessDeclining
• QuadraticFluidDamping
• Clearance
Specifications
.ARIDE.parts.ac_hydro_bushing
Parameters
Parameter: Type: Function:
property_file string variable name of property file
bushing_property_file string variable name of the bushing property file
super_impose_bushing integer variable togggle if the spline from the original bushing property file will be superimposed in the direction of the hydro component
hydro_coordinate string variable hydro direction coordinate
t_preload_x real variable translational preload
51Working with ComponentsHydromounts
Input Parameters
Output Parameters
none
Objects
t_preload_y real variable translational preload
t_preload_z real variable translational preload
r_preload_x real variable rotational preload
r_preload_y real variable rotational preload
r_preload_z real variable rotational preload
t_offset_x real variable translational offset
t_offset_y real variable translational offset
t_offset_z real variable translational offset
r_offset_x real variable rotational offset
r_offset_y real variable rotational offset
r_offset_z real variable rotational offset
i_geoMarker Marker geometry ref marker
j_geoMarker marker geometry ref marker
geoRadius real variable geometry radius
geoLength real variable geometry length
Input parameter: Type: Function:
i_marker object variable action marker
j_marker object variable marker whose parent is the reaction part and reference marker
Object: Type: Function:
data_array Adams array array to pass the scaling factors and preloads to the field subroutine
fx_spline Adams spline force spline set to 0, depent on Hydro_Direction
fy_spline Adams spline set to 0, depend on Hydro_Direction
fz_spline Adams spline set to 0, depend on Hydro_Direction
Parameter: Type: Function:
Adams/Car RideHydromounts
52
tx_spline Adams spline torque spline
ty_spline Adams spline
tz_spline Adams spline
hydro_test_data_cdyn Adams spline stiffness
hydro_test_data_phase Adams spline angle
hydro_identification_data_cdyn Adams spline stiffness
hydro_identification_data_phase
Adams spline angel
i_graphic revolution graphics on I part
j_graphic cylinder graphic on J part
disp_request request displacement request
velo_request request velocity request
force_request request force request
output_request request hydroForce, Fluidvelocity, Fluiddisplacement
field field standard bushing field subroutine (900)
hydro_force_i sforce force representing the hydro path in z direction (action only)
hydro_force_j sforce hydro_force_i
hydro_disp state variable displacement difference between force marker and channel fluid displacement including clearance
hyrdo_diff_channel_disp diff displacement state of fluid in channel
hydro_Direction string acting direction of hyrdo force: values : 'x' | 'y' | 'z'
hydro_DirectionMarker marker direction for hydro_force_i and _j
hydro_RubberStiffnes real_variable units: translational stiffness [N/mm]
hydro_RubberDamping real_variable units: translational damping [Ns/mm]
hydro_CouplingStiffness real_variable units: translational stiffness [N/mm]
hydro_LinearFluidDamping real_variable units: translational damping [Ns/mm]
hydro_QuadraticFluidDamping real_variable units: translational damping [Ns²/mm²]
hydro_CouplingStiffnessDeclining
real_variable units: [1/mm²]
hydro_EffectiveFluidMass real_variable units: [kg]
hyrdo_Clearance real_variable units: [mm]
Object: Type: Function:
53Working with ComponentsHydromounts
Request Definition
disp_request
user (905,1,i_marker,j_marker,field)
velo_request
user (905,2,i_marker,j_marker,field)
force_request
user (905,3,i_marker,j_marker,field)
Component name: Component units: Definition:
dx length x-distance between i_marker and j_marker
dy length y-distance between i_marker and j_marker
dz length z-distance between i_marker and j_marker
dm length magnitude
ax angle angle about x
ay angle angle about y
az angle angle about z
amag angle magnitude
Component name: Component units: Definition:
vx velocity x-velocity between i_marker and j_marker
vy velocity y-velocity between i_marker and j_marker
vz velocity z-velocity between i_marker and j_marker
vm velocity magnitude
wx angular_velocity
wy angular_velocity
wz angular_velocity
wm angular_velocity magnitude
Component name: Component units: Definition:
bushing_fx force x-force between i_marker and j_marker
bushing_fy force y-force between i_marker and j_marker
Adams/Car RideHydromounts
54
output_request
Subsystem Parameters
Design Parameters
bushing_fz force z-force between i_marker and j_marker
fm force magnitude
bushing_tx torque
bushing_ty torque
bushing_tz torque
tm torque magnitude
Component:Component
name:Component
units: Definition:
f2 hydroForce force force on i-marker of sforce hydro_force_i
f3 Fluidvelocity velocity state of hydro_diff_channel_velo
f4 Fluiddisplacement displacement state of hydro_diff_channel_disp
Top level: Sub level:
property_file
t_preload_(x-z)
r_preload_(x-z)
t_offset_(x-z)
r_offset_(x-z)
Parameter: Type: Function:
fx_scaling_factor real variable scaling factor (DOE)
fy_scaling_factor real variable scaling factor (DOE)
fz_scaling_factor real variable scaling factor (DOE)
tx_scaling_factor real variable scaling factor (DOE)
ty_scaling_factor real variable scaling factor (DOE)
tz_scaling_factor real variable scaling factor (DOE)
Hydro_RubberStiffnes_scaling_factor real_variable scaling factor (DOE)
Hydro_RubberDamping_scaling_factor real_variable scaling factor (DOE)
Component name: Component units: Definition:
55Working with ComponentsHydromounts
Macros
Create Macro: (call: acar template_builder instance ac_hydro_bushing create) Adams/Car Ride executes this macro when you create an instance of the definition ac_hydro_bushing.
Modify Macro: (call: acar template_builder instance ac_hydro_bushing modify) Adams/Car Ride executes this macro when you modify an instance of the definition ac_hydro_bushing.
Delete Macro: (call: acar template_builder instance ac_hydro_bushing delete) This macro deletes all the entities which have been created exclusively for the instance.
About Input Hydromount Property FilesThe block [MDI_HEADER] must be exactly the same as in the example input hydromount property file.
In the block [UNITS] you could modify LENGTH to be either m or mm.
The block [GENERAL] must contain all parameters listed in the sample file.
• The DEFINITION is always '.ride.attachment.ac_hydro_bushing'.
• The HYDRO_COORDINATE can be x, y or z. This parameter determines the acting direction of the hydro force with respect to the ac_hydro_bushing reference system.
• The BUSHING_PROPERTY_FILE is a standard ac_bushing property file that defines all six stiffness and damping components of a bushing.
• The SUPER_IMPOSE_BUSHING parameter can be set to:
• Off - The bushing component with the same direction as the hydro force component is set to zero.
• On - The bushing component is superimposed. The superimpose option is useful because it lets you add an impact stiffness to the hydro force component. During the identification process, the bushing stiffness and damping coefficients are not considered.
• The block [HYDRO_TEST_DATA] contains four columns of data. These are the measured data of the hydromount. For every amplitude you must have the same frequencies. The number of amplitudes is not fixed. You could also use a property file including the hydro parameters, which you can edit manually, or use a file that was written by a previous identification process. This
Hydro_CouplingStiffness_scaling_factor real_variable scaling factor (DOE)
Hydro_LinearFluidDamping_scaling_factor real_variable scaling factor (DOE)
Hydro_QuadraticFluidDamping_scaling_factor real_variable scaling factor (DOE)
Hydro_CouplingStiffnessDeclining_scaling_factor real_variable scaling factor (DOE)
Hydro_EffectiveFluidMass_scaling_factor real_variable scaling factor (DOE)
Hydro_Clearance_scaling_factor real_variable scaling factor (DOE)
Parameter: Type: Function:
Adams/Car RideHydromounts
56
allows you to first use rather larger error tolerances to speed up the process with relatively rough results before you run the identification process using those results as initial values with a smaller error tolerance. Or you could add additional test data later and redo the identification based on previously identified parameters.
Example Input Hydromount Property FileThe following is a sample input hydromount property file (extension .hbu). This sample file contains the minimum set of required data.
Learn about input hydromount property files.
$-----------------------------------------------------------MDI_HEADER[MDI_HEADER] FILE_TYPE = 'hbu' FILE_VERSION = 1.0 FILE_FORMAT = 'ASCII'$----------------------------------------------------------------UNITS [UNITS] LENGTH = 'mm' FORCE = 'newton' ANGLE = 'degrees' MASS = 'kg' TIME = 'second' $--------------------------------------------------------------GENERAL [GENERAL] DEFINITION = '.ride.attachment.ac_hydro_bushing' HYDRO_COORDINATE = 'z' BUSHING_PROPERTY_FILE = '<ride>/bushings.tbl/mdi_0001.bus' SUPER_IMPOSE_BUSHING = 'off' $------------------------------------------------------HYDRO_TEST_DATA [HYDRO_TEST_DATA]
{amplitude frequency cdyn phase}
0.100000 5.000000 620.0 7.7
0.100000 8.000000 652.0 16.2
0.100000 10.000000 776.0 20.4
0.100000 12.000000 911.0 20.2
0.100000 15.000000 1038.0 12.9
0.100000 20.000000 963.0 5.5
0.100000 25.000000 902.0 4.0
0.100000 30.000000 881.0 4.3
0.100000 40.000000 841.0 5.3
57Working with ComponentsHydromounts
Example Output Hydromount Property File The following is an example output hydromount property file. We left out the data for frequencies 4 - 39 Hz.
$-----------------------------------------------------MDI_HEADER [MDI_HEADER] FILE_TYPE = 'hbu' FILE_VERSION = 1.0 FILE_FORMAT = 'ASCII' $-----------------------------------------------------UNITS [UNITS] LENGTH = 'mm' FORCE = 'newton' ANGLE = 'degrees' MASS = 'kg' TIME = 'second' $-----------------------------------------------------GENERAL [GENERAL] DEFINITION = '.ride.attachment.ac_hydro_bushing' HYDRO_COORDINATE = 'z' BUSHING_PROPERTY_FILE = '<ride>/bushings.tbl/mdi_0001.bus' SUPER_IMPOSE_BUSHING = 'off' $-----------------------------------------------------HYDRO_PARAMETERS [HYDRO_PARAMETERS] RUBBER_STIFFNESS = 406.544598 RUBBER_DAMPING = 0.29298822 COUPLING_STIFFNESS = 282.526692 COUPLING_STIFFNESS_DECLINING = 0.071232 LINEAR_FLUID_DAMPING = 1.10642663 QUADRATIC_FLUID_DAMPING = 0.01834762 EFFECTIVE_FLUID_MASS = 51.416425 CLEARANCE = 0.0
0.100000 50.000000v 838.0 6.6
0.800000 5.000000 620.0 9.9
0.800000 8.000000 620.0 20.9
0.800000 10.000000 691.0 29.1
0.800000 12.000000 855.0 32.4
0.800000 15.000000 1085.0 25.2
0.800000 20.000000 1142.0 12.0
0.800000 25.000000 1100.0 7.0
0.800000 30.000000 1068.0 5.4
0.800000 40.000000 1020.0 5.3
0.800000 50.000000 1031.0 5.6
{amplitude frequency cdyn phase}
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$-----------------------------------------------------HYDRO_IDENTIFICATION_DATA[HYDRO_IDENTIFICATION_DATA]
$-----------------------------------------------------HYDRO_TEST_DATA [HYDRO_TEST_DATA]
{amplitude frequency cdyn phase}
0.100000 1.000000 404.863819 1.243071
0.100000 2.000000 399.691551 2.618614
0.100000 3.000000 388.455029 4.605679
... continue
0.100000 40.000000 713.285910 6.099968
0.500000 1.000000 404.772004 1.302907
0.500000 2.000000 399.309176 2.830528
0.500000 3.000000 389.903747 4.774778
... continue
0.500000 40.000000 716.810500 6.126563
1.000000 1.000000 404.777324 1.347649
1.000000 2.000000 399.296585 3.024592
1.000000 3.000000 390.207932 5.272207
... continue
1.000000 40.000000 700.288389 6.281555
{amplitude frequency cdyn phase}
0.100000 1.000000 392.000000 1.900000
0.100000 2.000000 393.000000 3.800000
0.100000 3.000000 393.000000 4.800000
... continue
0.100000 40.000000 773.000000 4.700000
0.500000 1.000000 389.000000 2.800000
0.500000 2.000000 386.000000 4.100000
0.500000 3.000000 385.000000 5.800000
... continue
0.500000 40.000000 734.000000 4.800000
1.000000 1.000000 379.000000 3.100000
59Working with ComponentsHydromounts
$OBJECTIVE_FUNCTION = 1.5051 $INTEGRATOR_ERROR = 0.0050 $STEADY_STATE_ERROR = 0.0100 $CONVERGENCE_TOLERANCE = 0.0050 $*** OPTIMIZATION ABORTED ***
1.000000 2.000000 377.000000 4.800000
1.000000 3.000000 378.000000 6.900000
... continue
1.000000 40.000000 700.000000 4.700000
{amplitude frequency cdyn phase}
Adams/Car RideHydromounts
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Tools
Adams/Car RideHydromount-Parameter Identification Tool
58
Hydromount-Parameter Identification Tool You can use this tool to identify the parameters of a hydromount model for given measurements of dynamic stiffness and loss angle dependent on frequency. The model used for the identification is identical to the model included in Adams. The output of the identification process is a property file that contains all the parameters of the Adams element.
If the start conditions have not been defined through manual input or through the property file, the identification routine starts with a linear model of the hydromount to determine the proper start conditions for the nonlinear model.
Learn more about the hydromount-parameter identification tool:
• About Hydromount Models
• Identification Process
• Identifying Hydromount Parameters
• Calculate Frequency Response
About Hydromount Models
You can use two kinds of hydromount models:
• Linear models - Consist of five parameters and do not include the clearance, quadratic fluid damping, and coupling stiffness declining terms, which are included in the complete nonlinear model.
• Coupling Stiffness
• Rubber Stiffness
• Linear Fluid Damping
• Rubber Damping
• Effective Fluid Mass
• Nonlinear models - Consist of up to eight parameters. The additional parameters to the linear model are:
• Coupling Stiffness Declining
• Quadratic Fluid Damping
• Clearance
59ToolsHydromount-Parameter Identification Tool
Mk Effective_Fluid_Mass
x Displacement(i_mar,j_mar,j_mar) - dz0x· Velocity(i_mar,j_mar,j_mar)
x1 Displacement(Mk)
v1 Velocity(Mk)
Kquad Coupling_Stiffness_Declining
Kb Linear_Coupling_Stiffness
Dk Linear_Fluid_Damping
Dk_quad Quadratic_Fluid_Damping
Kt Rubber_Stiffness
Ct Rubber_Damping
Coupling_Stiffness_Displacement_ x :
xx clearance+ x clearance+ 0 & x 0 x clearance– x clearance– 0 & x 0
0;else
=
Nonlinear_Coupling_Stiffness_Factor_q:
q
1 Kquad* x * x– Kquad 0
1 Kquad 0=
1 1 Kquad* x * x+ Kquad 0
=
Nonlinear_Fluid_Damping_Factor_c:
c Dk Dk_quad* v1+=
Coupling_Force:
Fcoupl x1 x– *Kb*q=
Differential_Equation_Fluid_Mass:
v1·
1– Mk * v1*c Fcoupl+ =
x1·
v1=
Adams/Car RideHydromount-Parameter Identification Tool
60
hydro_force Kt– * x Ct– * x· Fcoupl+=
61ToolsHydromount-Parameter Identification Tool
Note: The model is valid up to 100 Hz, depending on the quality of the input data. The frequency range of the input data should start below the first eigen frequency of the hydromount. The data supplied must be consistent. That is, for the first amplitude range there has to be a range of frequencies, for the next amplitude range the frequencies must be the same as the first amplitude range, and there must be the same number of rows of data, and so on. For example:
amplitude frequency
0.1 5
0.1 10
0.1 15
0.2 5
0.2 10
0.2 15
Adams/Car RideHydromount-Parameter Identification Tool
62
Identification Process The identification tool has three start conditions that determine the identification process:
• Without any Initial Parameters - All seven input parameters are zero.
• With Five initial Parameters - Five parameters are nonzero and the two nonlinear parameters are zero.
• With Seven initial Parameters - All seven input parameters are nonzero.
Identification Without any Initial Parameters
All input parameters in the interface are zero. Adams/Car Ride automatically sets all parameters to zero after loading a property file without the block [HYDRO_PARAMETERS]. . After you select Go, the process uses the linear model to identify the following five parameters:
• Rubber stiffness
• Rubber damping
• Coupling stiffness
• Linear fluid damping
• Effective fluid mass
The parameters are initial values for the complete model. The process continues with an initial guess of the nonlinear parameters: quadratic fluid damping and coupling stiffness declining, to fit the nonlinear behavior of the hydro force. The clearance remains at zero. At this point, you can stop the optimizer and modify any parameter. To check frequency response, select Calculate Frequency Response. You can repeat the process at any time.
Identification With Five Initial Parameters
You can enter the hydro parameters in the dialog box, or have them load from the property file (if it contains a block [HYDRO_PARAMETERS]). In this case, the process also starts based on the linear model and continues with the nonlinear model as described in the identification process without any initial parameters.
Identification With Seven Initial Parameters
You can enter the hydro parameters in the dialog box, or have them load from the property file (if it contains a block [HYDRO_PARAMETERS]). In this case, the process directly uses the complete nonlinear model. In this final part of the identification process, all seven parameters are varied and only the clearance remains fixed.
63ToolsHydromount-Parameter Identification Tool
Identifying Hydromount Parameters
To identify hydromount parameters:
1. Let Adams_install denote your Adams installation directory. For example, on Windows, this might be: "C:\MSC.Software\MD_Adams\2010\".
2. Do one of the following:
• On Windows, enter the following:
mdadams2010 python "Adams_install\python\win32\Lib\site-packages\mscarideidtool.py"
• On UNIX, let platform_name denote the Adams name of your platform
(you can find this by simply looking in the 'Adams_install/python/' directory). Then, enter:
mdadams2010 -c python <Adams_install>/python/<platform_name>/lib/python2.2/site-packages/mscarideidtool.py
3. Press F1 and then follow the instructions in the dialog box help for Hydromount-Parameter Identification.
4. Select Go.
Calculate Frequency ResponseAfter each iteration step, Adams/Car Ride automatically calculates the frequency response and updates the plots and parameters. You can manually modify each input parameter and calculate their frequency response.
Adams/Car RideIsolator-Parameter Identification Tool (IPIT)
64
Isolator-Parameter Identification Tool (IPIT)You can use this tool to identify the parameters of a Bushing model for given measurements of dynamic stiffness and loss angle, depending on frequency. The model used for identification is identical to the model included in Adams. The output of the identification process is a property file that contains all the parameters of the Adams element.
Learn more about the IPIT :
• About the Bushing Model
• Identification Process
• Identifying Bushing Parameters
• Calculate Frequency Response
About the Bushing ModelThe general bushing model uses the Bouc-wen model for amplitude dependency and Adams TFSISO elements for frequency dependency. You can use this tool to identify the parameters of the Bouc-wen model and the numerator and denominator coefficient parameters of the TFSISO elements for given measurements of dynamic stiffness and loss angle, depending on frequency and amplitude.
• TFSISO parameters
• The numerator coefficients
• The denominator coefficients
• Bouc-wen parameters
In coupled mode, the Bouc-wen hysteresis model consists of seven parameters
• Rigidity ratio
• Linear elastic viscous damping ratio
• Pseudo-natural frequency of the system
• Parameter controlling hysteresis amplitude
• Three parameters controlling hysteresis shape
The coupled Bouc-Wen hysteresis model is a system of nonlinear differential equations defined by:
In un-coupled mode, the Bouc-wen hysteresis model consists of one more additional parameter, . The un-coupled Bouc-Wen hysteresis model is a system of nonlinear differential equations
defined by:
a) f t 2nx· n2x 1 – n
2z+ +=
b) z· x· zn 1–
z– x· zn
ax·+–=
65ToolsIsolator-Parameter Identification Tool (IPIT)
Where the parameters of the system are:
Identification Process The Adams/Car Ride Isolator Parameter Identification Tool (IPIT) allows you to identify any bushing in Adams/Car Ride and Adams/Vibration. It should be noted that you can identify bushing parameters for one direction at a time. To identify the bushing parameters for more directions, you can run the optimizer multiple times. The resulting bushing property file (*.gbu, *.fbu, or other) can be used in for instance Adams/Car for further study.
Following steps explain how to identify bushing parameters using the IPIT:
• Step one: The bushing template file
• Step two: Prepare your GBU file for use with the IPIT
• Step three: Set-up the IPIT for the bushing parameter identification process
• Step four: Calculate FRF and/or Run the Optimizer
Step one: The bushing template file
The IPIT uses a python template file to calculate the bushing response using Adams/Solver (C++ or F77). This python template file contains Adams/Solver ACF and ADM files. You can use Adams/Solver
a) f t 2nx· n2x n
2z+ +=
b) z· x· zn 1–
z– x· zn
ax·+–=
n
a
n
: rigidity ratio 0 1 or hysteresis force scale
: linear elastic viscous damping ratio 0 1 : pseudo-natural frequency of the system (rad/s)
: parameter controlling hysteresis amplitude
: parameters controlling hysteresis shape n 1 : linear force scale
Note: The data supplied must be consistent. That is, for the first amplitude range there has to be a range of frequencies, for the next amplitude range the frequencies must be the same as the first amplitude range, and there must be the same number of rows of data, and so on. For example:
amplitude frequency0.1 50.1 100.1 150.2 50.2 100.2 15
Adams/Car RideIsolator-Parameter Identification Tool (IPIT)
66
statements and add for instance your own user libraries for bushings in this template. The example python template file is located in: adams_install/python/Arch/Lib/site-packages/bushing_templates.py, where Arch is your platform (win32, linux32, etc.) and install is your Adams installation folder. If you open the template file, you will find a number of template variables including description at the beginning of this file. You may study the example template to understand how the template variables are used to create a bushing model used in combination with the IPIT. Modification of the template file allows you to include your own bushing model. The IPIT uses two important python string variables acftext and admtext to recognize your ADM and ACF templates.
The example python template file has one ACF template and two ADM sample templates. The admtext python string variable lists the ADM template for the Adams/Car Ride general bushing which is used by the IPIT to identify the general bushing parameters (example template file for BUSHING_COORDINATE = 'x' or 'y' or 'z' or 'ax' or 'ay' or 'az'). The admtext2 python string variable lists the ADM template for the Adams/Car Ride hydro-mount. The IPIT uses this template to identify the hydro mount parameters (example template file for BUSHING_COORDINATE = 'g').
The python template file can contain multiple ACF and ADM templates, but the IPIT only uses the template represented by the python string variables acftext and admtext.
It is also possible to create a customized python template and hook-up it to the IPIT by defining environment variable IPIT_TEMPLATE_PATH. The user template file name is restricted to 'user_bushing_templates.py' and it should reside in the directory referred by environment variable IPIT_TEMPLATE_PATH (for example, IPIT_TEMPLATE_PATH=C:/users/IPIT_user_dir). If the path or file is not accessible or incorrect, IPIT uses the default template from the installation. IPIT also informs the user about which template it is using by printing a message in the command shell.
Step two: Prepare your GBU file for use with the IPIT
It should be noted that the IPIT only identifies the bushing parameters for one direction at a time as specified in the GBU file. The following shows a number of important parameters that must be defined in the GBU property file.
BUSHING_COORDINATE = x/y/z/ax/ay/az/g
• Chose any of the following co-ordinate for identification of the bushing
• If co-ordinate x/y/z/ax/ay/az, make sure your admtext variable points to the general bushing ADM template as the IPIT uses the Bouc-Wen and TFSISO template variables.
• If co-ordinate g, make sure your admtext variable points to the hydro mount ADM template (Replace admtext2 with admtext and vice versa in bushing_templates.py) as the IPIT uses <<DV_1>> to <<DV_256>>
• You must specify the bushing co-ordinate.
BUSHING_SHAPE=0/1
• Only rectangular coupling is supported in IPIT
• 0 or 1 is rectangular coupling, 2 is cylindrical coupling and 3 is spherical coupling
67ToolsIsolator-Parameter Identification Tool (IPIT)
• Defaults to '0'
BUSHING_COUPLING=0/1
• Do you want coupling of Bouc-Wen force? 1: Yes, 0: No
• More details can be found in the Bouc-wen model description. Parameter 'k' is now used.
• Defaults to '0'
[UNITS]
• Please specify units of your test data under this block
• Phase is in degrees
• Dynamic stiffness in units as specified
• No default
[DAMPING]
• Specify Linear damping as loss angle
• Default is '0.0'
[PRELOAD]
• Specify preload in units under block [UNITS]
• Default is '0.0'
[OFFSET]
• Specify offset in units under block [UNITS]
• Default is '0'
[SPLINE_SCALES]
• Do you want to scale the spline force? How much?
• Used by IPIT while running Strategy
• Defaults to 0.0
[HYST_SCALES]
• Do you want to scale Bouc-wen/Hysteresis force? How much?
• Used by IPIT while running Strategy
• Defaults to 0.0
[TFSISO_SCALES]
• Do you want to scale TFSISO force? How much?
• Used by IPIT while running Strategy
• Defaults to 0.0
Adams/Car RideIsolator-Parameter Identification Tool (IPIT)
68
[FX_CURVE]
• Specify your X directional spline here
• Must be specified if BUSHING_COORDINATE = 'x', otherwise optional
• No default
[FY_CURVE]
• Specify your X directional spline here
• Must be specified if BUSHING_COORDINATE = 'y', otherwise optional
• No default
[FZ_CURVE]
• Specify your X directional spline here
• Must be specified if BUSHING_COORDINATE = 'z', otherwise optional
• No default
[TX_CURVE]
• Specify your X directional spline here
• Must be specified if BUSHING_COORDINATE = 'ax', otherwise optional
• No default
[TY_CURVE]
• Specify your X directional spline here
• Must be specified if BUSHING_COORDINATE = 'ay', otherwise optional
• No default
[TZ_CURVE]
• Specify your X directional spline here
• Must be specified if BUSHING_COORDINATE = 'az', otherwise optional
• No default
[BUSHING_PARAMETERS]
• Specify your Bouc-wen and TFSISO parameters here
• Must be specified if BUSHING_COORDINATE = x/y/z/az/ay/az
• No default
[BUSHING_IDENTIFICATION_DATA]
• Specify your identified data here if any
• If not given, IPIT outputs its calculated identified data under this block
69ToolsIsolator-Parameter Identification Tool (IPIT)
• Optional
[BUSHING_TEST_DATA]
• Specify your test data here
• You must specify this block
• No default
[BUSHING_SCALE_DATA]
• Specify your scale data here
• Used by IPIT while running Strategy
• Defaults to 1.0 for all dynamic stiffness and phase values for given amplitudes and frequency
Step three: Set-up the IPIT for the bushing parameter identification process
There are various controls provided in the IPIT for identification of the bushing parameters which may help the user to setup the IPIT for specific needs. For example, Error Control tab lists the optimizer and integrator errors and you can set these as you desire. Under Solver Control tab, you can make choice on solver, sensor and method. Under Strategy control tab, you can activate the built-in fitting strategy by setting Estimate Initial Parameters to 'yes'. If you activate strategy, the IPIT identifies bushing parameters in following order:
a. Identify the Bouc-Wen model parameters using a limited number of test data points.
b. Identify the TFSISO using a limited number of test data points.
c. Identify both Bouc-Wen and TFSISO model parameters using the results from steps a. and b. as initial values for the Bouc-Wen and TFSISO model.
Steps a. and b. are relatively fast and may already give acceptable fit-results. Step c. will take most time as all parameters are identified using all test data. Please refer F1 help to find further details about each control.
Step four: Calculate FRF and/or Run the Optimizer
Select the Calculate Frequency Response button to calculate and plot the dynamic stiffness and phase angle. Select the "Go" button to start the bushing parameter identification process.
You can also export Adams/View CMD files to define your own fit-strategy using File -> Export CMD and run this file in batch mode as follows;
Windows: mdadams2010 acar ru-acar b abcd.cmd
UNIX: mdadams2010 -c acar ru-acar b abcd.cmd
You can modify the CMD file according to your needs. For more information, see the comments in the exported CMD file.
Adams/Car RideIsolator-Parameter Identification Tool (IPIT)
70
Identifying Bushing Parameters
To identify bushing parameters:
1. Let adams_install denote your Adams installation directory. For example, on Windows, this might be: "C:\MSC.Software\MD_Adams\R4\".
2. Do one of the following:
• On Windows, enter the following:
mdadams2010 python "adams_install\python\win32\Lib\site-packages\boucwenbushing.pyc"
• On UNIX, let platform_name denote the Adams name of your platform (you can find this by simply looking in the adams_install/python/ directory). Then, enter:
mdadams2010 -c python <adams_install>/python/<platform_name>/lib/python2.5/site-packages/boucwenbushing.pyc
3. Press F1 and then follow the instructions in the dialog box help for Isolator-Parameter Identification.
4. Click Go.
Calculate Frequency ResponseAfter each iteration step, Adams/Car Ride automatically calculates the frequency response and updates the plots and parameters. You can manually modify the IPIT input fields and calculate the frequency response.
Using with Adams/ChassisThe Isolator-Parameter Identification Tool (IPIT) uses TeimOrbit property files. Since Adams/Chassis is only compatible with XML property files, the tool will allow you to read in XML formatted property files and to perform the required conversions. When saving the property file, IPIT will save the data into an XML bushing property file, which can be imported in the Adams/Chassis connector editor.
71ToolsRoad-Profile Generation Tool
Road-Profile Generation ToolThe Adams/Car Ride tool for generating road profiles with roughness uses a mathematical model developed by Sayers [1, 2]. The model is empirical: it is based on the observed characteristics of many measured profiles of roads of various types. The model also provides for the synthesis of profiles for both the left and right wheeltracks.
Learn more about the road-profile generation tool:• About the Road-Profile Generation Tool
• Parameter Variables for Sayers Roughness Model
• Generating a Road Profile
• References
About the Road-Profile Generation Tool
For a single wheeltrack, the model assumes that the power-spectral density (PSD) of the displacement
(elevation) of a road profile, , is a function of wavenumber, , given by the equation:
: (1)
Therefore, it is assumed that roughness comes from three components. Each is obtained from an independent source of white noise, that is, random numbers.
• The first component, with amplitude , is white-noise elevation.
• The second, with amplitude , is white-noise slope (velocity) that is integrated once with
respect to time.
• The third, with amplitude , is white-noise acceleration that is integrated twice with respect to
time.
The letter above denotes Gaussian. Each sequence of random numbers is assumed to have a Gaussian
distribution with a mean value of zero and a standard deviation, , of:
: (2)
where:
• is a white-noise amplitude for one of the three terms in Equation 1 ( )
• is the interval between samples, expressed in the inverse units of those used for wavenumber
Gd
Gd v Ge
Gs
2 2-----------------
Ga
2 4-----------------+ +=
Ge
Gs
Ga
G
G2-------=
G Ge, Gs, Ga
Adams/Car RideRoad-Profile Generation Tool
72
As explained in Reference 2, profiles for the left and right wheeltracks are obtained by the following method, which maintains the proper coherence between them:
1. Filtering and summing white-noise sources generates three uncorrelated profiles, as described statistically by the specified wheeltrack PSD, that is, the specified values of , , and . Adams/Car Ride scales them such that their PSD amplitudes are half of the wheeltrack PSD. The first of these is designated . It is not filtered further. The remaining two profiles are subsequently processed by filtering.
2. A cut-off wavenumber, , is established for the subsequent filtering as
: (3)
where is the correlation baselength. The recommended value for is 5.0 (m).
3. The second uncorrelated profile is filtered with a low-pass filter with cut-off wavenumber . The resulting profile is designated .
4. The third uncorrelated profile is filtered with a high-pass filter with cut-off wavenumber . The resulting profile is designated .
5. The left and right wheeltrack profiles, and , are then obtained from these three components:
(4)
(5)
Parameter Variables for Sayers Roughness Model
Example values for the parameters , , and . are shown in the following table, which is taken
from Appendix E of Reference 1. The terms flexible and rigid, as descriptions of surface types, approximately correspond to asphalt and Portland-cement concrete (PCC) roads, respectively. The symbol IRI in the table denotes International Roughness Index, which is a widely used road-roughness standard that was developed with The World Bank. The IRI is discussed in detail in Reference 3.
Table 1 Example Parameter Values for the Sayers Roughness Model
IRI Ge Gs Ga
Surface type
Smooth Flexible
75 1184 0 6 0
Flexible 150 2367 0 12 0.17
Ge Gs Ga
Zv1
2
21
LB 2-------------=
LB LB2
Zv22
ZcZL ZR
ZL Zv1 Zv2 Zc+ +=
ZR Zv1 Zv2 Zc–+=
Ge Gs Ga
inmi------ mm
km--------- m3
cycle------------- 10 6– m
cycle------------- 10 6– 1
m cycle ----------------------------- 10 6–
73ToolsRoad-Profile Generation Tool
As explained in Reference 1, the range of values shown for the slope coefficient mainly reflects the roughness range covered by the roads in each category. The other two coefficients describe additional roughness increasing for very short and very long wavelengths. Amplitudes of very long wavelengths,
indicated by nonzero values of , might be associated with the quality of grading performed in
building the road. High amplitudes of very short wavelengths, typified by nonzero values of , are
commonly caused by surface defects that are extremely localized, such as faults, tar strips, and potholes.
Generating a Road Profile
To generate a road profile:
1. From the Ride menu, point to Tools, and then select Road-Profile Generation.
2. Press F1 and then follow the instructions in the dialog box help for Road-Profile Generation.
3. Select OK.
References 1. Gillespie, T.D., et.al., "Effects of Heavy-Vehicle Characteristics on Pavement Response and
Performance." NCHRP Report 353, Transportation Research Board, Washington D.C., 1993, 126 pp.
2. Sayers, M.W., "Dynamic Terrain Inputs to Predict Structural Integrity of Ground Vehicles." UMTRI Report No. UMTRI-88-16, April 1988, 114 pp.
3. Sayers, M.W. and Karamihas, S.M., "Interpretation of Road Roughness Profile Data." Final Report SPR-2 (159), Federal Highway Administration, Contract No. DTFH 61-92-C00143, January 1996.
4. MTS Systems Corporation: www.mts.com/rpc3/file_formats or Adams/Durability online help: Referencing Test Data
Rough Flexible
225 3551 0.003 20 0.20
Smooth Rigid
80 1263 0 1 0
Rigid 161 2541 0.1 20 0.25
Rough Rigid 241 3804 0.1 35 0.3
IRI Ge Gs Ga
Ga
Ge
Adams/Car RideRoad-Profile Generation Tool
74
1Dialog Box - F1 Help
Dialog Box - F1 Help
Adams/Car RideAbout the Bushing Model
2
About the Bushing Model Below is an outline of the frequency-dependent bushing model.
with
with
F1 C1 x=
F2 C2 z d2 z·+ d1 x· z·– = =
Flin F1 F2+=
C2C1------- d2
d1------ d1
C1-------=;=;=
Flin C1 x d1 x· z·– + C1 xd1C1------- x· z·– +
C1 x x· z·– + = = =
z·1
1 +------------ x·
--- z–
=
3Dialog Box - F1 HelpAbout the Bushing Model
Constant stiffness in frequency-dependent term of F_lin:
The static forces are computed by the splines from the property file; this is the first term, , of
. But the second term, , is computed with a constant value C1, obtained at the
zero position of the spline.
C1 xFlin C1 x· z·–
Adams/Car RideAbout the Bushing Model
4
Reference frequency at 15 Hz for loss angle
The coefficients alpha, beta, gamma are linear scaled to obtain the loss angle at 15 Hz. The dynamic stiffness can not be controlled. The stiffening factor is coupled with the loss angle. For example:
Loss Angle [Deg]: Stiffening factor:
5 1.17
10 1.34
5Dialog Box - F1 HelpAbout the Bushing Model
Adams/Car RideAdams/Controls Plant Export
6
Adams/Controls Plant Export Exports the Adams/Controls plant files. Adams/Controls save the input and output information in an .m (for MATLAB) or .inf file (for Easy5).
For the option: Do the following:
Damper Specify the name of GSE Damper instance.
File Prefix Enter the prefix for the .m, and .inf files that Adams/Controls create.
Target Software Select one of the following:
• Easy5
• MATLAB
Adams Host Enter the name of the host machine from which the Adams plant is being exported. This host name is used if you choose TCP/IP-based communication to perform cosimulation or function evaluation between Adams and MATLAB or Easy5.
7Dialog Box - F1 HelpIsolator-Parameter Identification
Isolator-Parameter Identification
Ride Tools Isolator-Parameter Identification
Identifies the parameters of the bushing model for given measurements of dynamic stiffness and loss angle, depending on frequency. Learn more about Isolator-Parameter Identification Tool (IPIT).
For the option: Do the following:
File Load File Load a bushing input file. See About Input Bushing Property Files.
File Save File Save the bushing to a file. See an Example Output Bushing Property File.
File Export CMD Export the bushing CMD file. Use this option to create a user strategy by editing the file and to run the IPIT in batch mode and/or from command line. You can import the bushing CMD file in Adams/View as well.
File Quit Quit IPIT tool.
Help About About IPIT tool.
Help About Adams/Car Ride IPIT
Help about Adams/Car Ride IPIT.
Input Parameters:
Calculate Frequency Response
Select to calculate the frequency response data with the current input parameters that are displayed in the text boxes. You can manually change those parameters and use this button to see the influence on the frequency response.
Error Control:
User Pars Enter the mscads optimizer user parameters to tune mscads for your problem
Convergence Tolerance Enter the tolerance for which the objective function is considered converged.
Max Optimizer Loops Enter the maximum number of iterations to find the optimum.
Max Function Evaluations Enter the allowed maximum function evaluations.
Max Cycles Enter the maximum cycles. The maximum cycles and frequency govern the simulation end time.
Integrator Error Enter the Adams/Solver integration error.
Solver Control:
Solver Choice Select Solver.
Keep Files Select 'Yes' to save Adams/Solver related files.
Sensor Activate/Deactivate sensor.
Method Select method to calculate the frequency responses.
Adams/Car RideIsolator-Parameter Identification
8
Strategy Control:
Estimate Initial Parameters If set to 'yes', the IPIT uses the built-in strategy to estimate initial parameters before it starts an optimization for all parameters.
Go Select to start the identification process.
Stop Select to stop the identification process.
Plot Displays the frequency response of the model; the dynamic stiffness in the plot named Cdyn and the loss angle in the plot named Phase.
Data Displays the input file and the frequency response data.
For the option: Do the following:
9Dialog Box - F1 HelpComponent Analysis
Component AnalysisSets up a component analysis.
Results with 1 mm amplitude and 5 Hz
For the option: Do the following:
Component Assembly Select the component assembly you want to analyze. The menu shows all open component assemblies.
If it shows No component assemblies, then you must open or create an assembly. You can use either of the following ways to open or create an assembly:
• File -> New or File -> Open
• tool, described next
Right-click to display the following, left-click to select any of them:
• - Select an existing assembly and use it for the component analysis. This is an alternative method to selecting it directly from the Component Assembly menu.
• - Open an assembly from a file. Once loaded, Adams/Car Ride displays the assembly in the Component Assembly menu.
• - Create a new assembly. Once created, the new assembly will be displayed in the Component Assembly menu.
Output Prefix Enter a string that specifies the Analysis Output Name. The string can contain only alphanumeric characters and underscores (_).
Actuation Type This option is followed by either force or motion, indicating how the test rig is configured to stimulate the component during the analysis. This simply displays the setting in the Actuation Type pull-down menu on the Component Analysis: Set Up Test Rig dialog box.
Adams/Car RideComponent Analysis
10
Excitation Function Select an analysis type:
• Set of Frequencies - Perform a discrete frequency and amplitude sweep. You use this analysis to determine the loss energy and dynamic stiffness of a component.
• Range of Frequencies
• Continuous Sweep
• Quasi Static
• User Function
• Damper Sweep
If you select Set of Frequencies, Adams/Car Ride displays the following options:
Frequency Enter one or a list of frequency values. If you enter a list of frequencies, make sure that you separate each entry by a comma (1.0, 2.0, 3.0, ...).
Maximal Cycles Enter the maximum number of cycles to be performed during one analysis. If you enable the Energy Sensor, the simulation might stop before reaching the maximum number of cycles because the model has reached a steady-state condition.
Steps per Cycle Enter the desired number of steps per cycle.
Excitation Amplitude Enter one or a list of amplitude values. If you enter a list of amplitudes, make sure that you separate each entry by a comma (1.0, 2.0, 3.0, ...).
Phase Enter the phase of the excitation function. Adams/Car Ride applies the phase with an initial step.
Loop over Select the inner loop of a series of analyses (Amplitude or Frequency). This produces loss angle and dynamic stiffness over amplitude or frequency.
For the option: Do the following:
11Dialog Box - F1 HelpComponent Analysis
Energy Sensor Select one of the following:
• On
• Off
The analysis stops either as soon as loss energy converges or after completion of the maximum number of cycles.Use the Energy Sensor to watch the convergence of the force signal instead. Adams/Car Ride calculates the energy error, E, for one motion channel as follows:
E(cycle n) = (E(cycle n-1) + 7 * (loss_energy(n) - loss_energy(n-1)) / loss_energy(n)) / 8
If the energy error is less than 2.0e-3, the sensor stops the analysis because the model has converged on a steady-state response.
Measuring Method Select a method for measuring the loss angle and dynamic stiffness:
• Min-Max-Method - Combines the integral of the hysteresis with the minimum and maximum of the force. For a linear component, the result is usually equal to the fourier method. For a nonlinear component, the result diverges slightly. Learn more about the Min-Max Method.
• Fourier-Method - Is a first-order fourier analysis used to approximate the force signal with a harmonic force function. Learn more about the Fourier Method.
See the Force vs Displacement for Linear Damper.
If you select Range of Frequencies, Adams/Car Ride displays the following options:
Start Enter the start frequency.
Incr Enter the increment between frequencies.
End Enter the end frequency.
Maximal Cycles Enter the maximum number of cycles to be performed during one analysis. If you enable the Energy Sensor, the simulation might stop before reaching the maximum number of cycles because the model has reached a steady-state condition.
Steps per Cycle Enter the desired number of steps per cycle.
Excitation Amplitude Enter one or a list of amplitude values. Adams/Car Ride holds the amplitude constant during one analysis, and during the next analysis it chooses the next frequency in the list.
If you enter a list of amplitudes, make sure that you separate each entry by a comma (1.0, 2.0, 3.0, ...).
For the option: Do the following:
Adams/Car RideComponent Analysis
12
Phase Enter the phase of the excitation function. Adams/Car Ride applies the phase with an initial step.
Loop over Select the inner loop of a series of analyses (Amplitude or Frequency). This produces loss angle and dynamic stiffness over amplitude or frequency.
Energy Sensor The analysis stops either as soon as loss energy converges or after completion of the maximum number of cycles.
Measuring Method See the explanation for Measuring Method above.
If you select Continuous Sweep, Adams/Car Ride displays the following options:
Start Enter the start frequency.
End Enter the end frequency.
End Time Enter the end time for your simulation.
Number of Steps Enter the total number of steps. Make sure that you have sufficient output steps at the highest frequency so that important output data is not lost (anti-aliasing).
If you select Quasi Static, Adams/Car Ride displays the following options:(see example results for a quasi-static test)
End Time Enter the end time for your simulation.
Number of Steps Enter the total number of steps. Make sure that you have sufficient output steps at the highest frequency so that important output data is not lost (anti-aliasing).
Amplitude Enter the amplitude of the SAWTOOTH function.
Velocity Enter the velocity of the SAWTOOTH function.
Max. Acceleration Enter the maximum acceleration of the SAWTOOTH function at the reversal point.
For example:
y-axis: A = 1 mm, Vel = 0.5 mm/sec
z-axis: A = 2 mm, Vel = 0.5 mm/sec
Maximal acceleration: translational = 1 mm/sec
The max. acceleration should satisfy: (vel * vel) / acc < ampl / 4
The excitation function uses the HAVERSIN step to meet the reversal point.
If you select User Function, Adams/Car Ride displays the following options:
End Time Enter the end time for your simulation.
For the option: Do the following:
13Dialog Box - F1 HelpComponent Analysis
Number of Steps Enter the total number of steps. Make sure that you have sufficient output steps at the highest frequency so that important output data is not lost (anti-aliasing).
Amplitude Enter a function expression.
Select to use the Function or Expression Builder to define a function. For information on the Function or Expression Builder, see Function Builder.
If you select Damper Sweep, Adams/Car Ride displays the following options:(See example results for a Damper Sweep test.)
Frequency Alpha Factor Factor alpha determines the frequency acceleration. The displacement function is used for the Monroe Damper Model in the Chirps test:
x(time) = A * sin( 4 * PI * time /( 2 * T0 - time )), 0 < time < T/2
= -A * sin( 4 * PI * (T - time) / ( 2 * T0 - T + time)), T/2 < time < T
with:
• A = Amplitude
• T = End Time
• T0 = T / ( 4 * ( 1 - 1 / (2**alfa) ) )
End Time Enter the end time for your simulation.
Number of Steps Enter the total number of steps.
Other Monroe tests are:
Bleed: 1 Hz, A = 50 mm
Blow-off: 3 Hz, A = 50 mm
Compression: 12 Hz, A = 5 mm
Friction: damper velocity = 1 - 2 mm/sec.
VDA damper test at the test field:
Test: max. Damper velocity (mm/sec) - Amplitude (mm)
Friction 2.6 - 10
Gas Force 2.6 - 10
For the option: Do the following:
Adams/Car RideComponent Analysis
14
The gas and friction force definition:
Gas Force = (Fmax + Fmin) / 2
Friction Force = Fmax - Fmin
Forces Fmax and Fmin are measured at middle of max- and min displacement.
These tests can be performed with the Excitation function: Set of Frequencies with f = vmax/(2*PI*A) = 0.04138 Hz.
Excitation frequencies for the VDA Velocity Test with Amplitude = 50 mm:
Demand velocity (mm/sec): Excitation frequency (Hz):
52 0.1655211
131 0.4169860
262 0.8339719
393 1.2509579
524 1.6679438
1047 3.3327045
To get the pure damper forces, the results must be reduced by the gas force.
Keep Files Select to keep the analysis files on your disk.
Select to display a dialog box where you can add multi-line comments to any entity, to describe its purpose and function. Adams/Car Ride displays different comments dialog boxes, depending on the entity type for which you want to record comments:
• If recording comments for modeling entities in Standard Interface, Adams/Car Ride displays the Entity Comments dialog box.
• If recording comments for any other entity type, Adams/Car Ride displays the Modify Comment dialog box.
Learn more about Recording Comments.
For the option: Do the following:
15Dialog Box - F1 HelpComponent Analysis: Set Up Test Rig
Component Analysis: Set Up Test RigRide -> Component Analysis -> Component-Model Test Rig -> Set Up Test Rig
Lets you set up the test rig for a component analysis. Learn about the Component Test Rig.
Results with 1 mm amplitude and 5 Hz
For the option: Do the following:
Component Assembly Select the component assembly you want to analyze. The menu shows all open component assemblies.
If it shows No component assemblies, then you must open or create an assembly. You can use either of the following ways to open or create an assembly:
• File -> New or File -> Open
• tool, described next
Right-click to display the following, left-click to select any of them:
• - Select an existing assembly and use it for the component analysis. This is an alternative method to selecting it directly from the Component Assembly menu.
• - Load an assembly from a file. Adams/Car Ride displays the assembly in the Component Assembly menu.
• - Create a new assembly. Adams/Car Ride displays the assembly in the Component Assembly menu.
Actuation Type Select one of the following:
• Force Driven
• Motion Driven
If you select Force Driven, Adams/Car Ride displays the following options:
Constraint Select one of the following:
• Force - Implements a force in this direction.
• Locked - Locks this degree of freedom.
• Released - Releases this degree of freedom.
Adams/Car RideComponent Analysis: Set Up Test Rig
16
Initial Value Select whether you want to set the initial Displacement or Preload, and set its numerical value.
If you select Motion Driven, Adams/Car Ride displays the following options:
Constraint Select one of the following:
• Motion - Implements a motion in this direction.
• Locked - Locks this degree of freedom.
• Released - Releases this degree of freedom.
Initial Value Select whether you want to set the initial Displacement or Preload, and set its numerical value.
Select to display a dialog box where you can add multi-line comments to any entity, to describe its purpose and function. Adams/Car Ride displays different comments dialog boxes, depending on the entity type for which you want to record comments:
• If recording comments for modeling entities in Standard Interface, Adams/Car Ride displays the Entity Comments dialog box.
• If recording comments for any other entity type, Adams/Car Ride displays the Modify Comment dialog box.
Learn more about Recording Comments.
For the option: Do the following:
17Dialog Box - F1 HelpComponent Test Rig
Component Test RigThe component test rig has up to six prescribed motions to determine the dynamic stiffness and loss angle for each degree of freedom of an elastic component.
The test rig consists of an upper and lower part. The lower part is fixed to ground and the upper part is controlled by a six degree-of-freedom motion marker. You can activate or deactivate each motion degree of freedom.
The test component in the test-rig assembly defines its own mount location and communicates the location through a marker communicator. The upper mount point is at the upper part and the lower mount point is at the lower mount part of the test rig.
You can initialize multiple runs in one setup. For each simulation, you can compare measured data of dynamic stiffness and loss angle, or loss work, with the simulation result. This means that the component model being tested is excited with constant frequency and amplitude sinusoid until either of these conditions are met:
• The excitation has been repeated N times where N = the maximum number of cycles you set.
• The energy sensor is on and the loss angle has converged according to the error criteria in the help entry for the Energy Sensor.
Convergence means that the component model has reached steady-state behavior. Dynamic stiffness and loss angle are only defined for a steady-state condition.
The test rig is also used for quasi-static analyses, which maintain a constant velocity motion between a minimum and maximum displacement. You can define a preload for each motion degree of freedom or for an initial displacement. The motion can be a constant-frequency or a linear-frequency sweep. The motion is defined between the marker lower_mount_point and upper_mount_point with respect to cfs_testrig_reference.
Analysis Types and Test-Rig Setup
Note: You must set up the test rig before you can run a meaningful analysis.
Test rig setup: Excitation function: Driver type: Results:
Analysis types:
Constr. Initial Displ.
Preload Amplitude Phase Motion Force Loss Angle
Std. Req
Set of Frequencies
x x x A set of amplitudes
Initial Step
x x x x
Range of Frequencies
x x x A set of amplitudes
Initial Step
x - x x
Adams/Car RideComponent Test Rig
18
The test-rig setup determines the constraints for each component as motion, locked, or constraint released. The initial displacement and preload are exclusive options. The initial displacement or preload is applied during the initial static and its values are used as the start condition for the subsequent analysis.
The constraints you can choose depend on the actuation type:
• Motion - The available constraints are: Locked, Released, or Motion. The initial displacement or preload is only for Locked or Motion constraints.
• Force - The available constraints are: Locked, Released, or Force. The initial displacement or preload is only for Locked constraint. The Force option allows you to enter a force offset value.
Excitation Function
The excitation function is defined in the dialog box, Component Analysis.
Amplitude - The amplitude is a single value or a set of amplitudes separated by commas. Each amplitude performs an analysis with the same test rig setup.
Phase - The phase of a sinusoidal motion during a constant or sweep frequency is achieved in different ways. The motion always starts with velocity = 0 and increases in a quarter of a period to the specified amplitude value. The sine function starts after a fourth of a period minus the phase shift value. The initial displacement or preload is held during the static analysis. The sinusoidal motion starts at the initial displacement.
Continuous Sweep
x x x A set of amplitudes
Direct x - - x
Quasi Static x x x A set of amplitudes
Initial Step
x - - x
User Function
x x x - - x x - x
Damper Sweep
x x x A set of amplitudes
- x - - x
Test rig setup: Excitation function: Driver type: Results:
19Dialog Box - F1 HelpComponent Test Rig
For example see the following figure: phase 0, 45 and 90 Deg, 1 Hz, initial displ. 0.
Direct - This method is used for the continuous sweep only. The sinusoidal motion starts with its phase and its initial displacement at time = 0, which causes a shift in displacement. The shift can be compensated with the initial displacement.
d = - amplitude * sin(phase)
If a preload was defined, the compensation is iterative.
Adams/Car RideComponent Test Rig
20
For example see the following figure: phase 0, 45 and 90 Deg, 1 Hz, initial displ. 0.
Results
Each analysis contains request data of the test rig. The test rig has two measure points: at the upper mount point, the I marker, and at the lower mount point, the J marker.
Name: Component: Units: Comments:
I_Force fx, fy, fz FORCE Force on I marker of motion generator Test_MOTION_* with respect to cfs_testrig_reference
= tx, ty, tz TORQUE Torque on I marker of motion generator Test_MOTION_t* with respect to cfs_testrig_reference
I_Displacement x, y, z LENGTH Displacement between I and J marker of Test_MOTION_* with respect to cfs_testrig_reference
= ax, ay, az ANGLE Angle with respect to cfs_testrig_reference
I_Velocity vx, vy, vz VELOCITY Velocity on I marker with respect to cfs_testrig_reference
21Dialog Box - F1 HelpComponent Test Rig
Construction Frames
The cfs_testrig_reference is the basis for motion and measurements.
= wx, wy, wz ANGULAR VELOCITY
Angular velocity
I_Acceleration acc_x, acc_y, acc_z ACCELERATION Acceleration on I marker with respect to cfs_testrig_reference
= dwx, dwy, dwz ANGULAR ACCELERATION
Angular acceleration
J_Force fx, fy, fz FORCE Force on J marker with respect to cfs_testrig_reference
= tx, ty, tz TORQUE
Force_Characteristics_$disp_comp
dyn_stiffness loss_angle
fmin
fmax
loss_energy
strain_energy
STIFFNESS
ANGLE
FORCE/TORQUE
FORCE/TORQUE
-
-
MinMax Method: user 112
Fourier Method: user 113
TestMotion_$disp_comp x, y, z,
ax, ay, az
AMPLITUDE
FREQUENCY
-
Analysis name = Transfer_Function_i
Result name = Force_Characteristics_$disp_comp
dyn_stiffness
loss_angle
Frequency
STIFFNESS
ANGLE
FREQUENCY
Last values of a Set or Range of Frequency Sweep i
Name:Location
dependency: Expression: Reference(s):
cfs_testrig_reference Delta location from coordinate
0,0,0 cis_upper_mount_point
Name: Component: Units: Comments:
Adams/Car RideComponent Test Rig
22
Expressions
The location expressions for cfs_lower_mount_point and cfs_upper_mount_point are nonstandard Adams/Car expressions. The cis_lower_mount_point and cis_upper_mount_point are marker communicators.
The displacement between cfs_upper_mount_point and cfs_testrig_reference is a zero displacement.
Test Rig Communicators
cfs_lower_mount_point Delta location from coordinate
0,0,0 cis_lower_mount_point
cfs_upper_mount_point Delta location from coordinate
0,0,0 cis_upper_mount_point
Name: Class:From minor
role: Matching name: Comment:
cis_lower_mount_point
marker inherit lower_mount_point mount point of component
cis_upper_mount_point
marker inherit upper_mount_point mount point of component
cos_lower mount inherit lower mount part
cos_upper mount inherit upper mount part
cis_active_x, _y, _z, _ax, _ay, _az
parameter
integer
inherit active_x, _y, _z, _ax, _ay, _az
constraint
active = 1,
deactive = 0
Name:Location
dependency: Expression: Reference(s):
23Dialog Box - F1 HelpExample Input Bushing Property File
Example Input Bushing Property FileThe following is a sample input Bushing property file (extension .gbu). This sample file contains the minimum set of required data.
$-----------------------------------------------------MDI_HEADER [MDI_HEADER] FILE_TYPE = 'gbu' FILE_VERSION = 2.0 FILE_FORMAT = 'ASCII' $-----------------------------------------------------UNITS [UNITS] LENGTH = 'mm' FORCE = 'newton' ANGLE = 'degrees' MASS = 'kg' TIME = 'second' $-----------------------------------------------------GENERAL [GENERAL] DEFINITION = '.aride.attachment.ac_general_bushing' BUSHING_COORDINATE = 'z' BUSHING_SHAPE = 0BUSHING_COUPLING = 1$------------------------------------------------------------DAMPING[DAMPING] X_LOSS_ANGLE = 0.0 Y_LOSS_ANGLE = 0.0 Z_LOSS_ANGLE = 0.0 TX_LOSS_ANGLE = 0.0 TY_LOSS_ANGLE = 0.0 TZ_LOSS_ANGLE = 0.0$------------------------------------------------------------PRELOAD[PRELOAD] X_PRELOAD = 0.0 Y_PRELOAD = 0.0 Z_PRELOAD = 0.0 TX_PRELOAD = 0.0 TY_PRELOAD = 0.0 TZ_PRELOAD = 0.0$-------------------------------------------------------------OFFSET[OFFSET] X_OFFSET = 0.0 Y_OFFSET = 0.0 Z_OFFSET = 0.0 TX_OFFSET = 0.0 TY_OFFSET = 0.0 TZ_OFFSET = 0.0$-------------------------------------------------------------SPLINE[SPLINE_SCALES]FX_CURVE_SCALE = 1.0FY_CURVE_SCALE = 1.0FZ_CURVE_SCALE = 1.0TX_CURVE_SCALE = 1.0TY_CURVE_SCALE = 1.0
Adams/Car RideExample Input Bushing Property File
24
TZ_CURVE_SCALE = 1.0$----------------------------------------------------------BOUC-WEN[HYST_SCALES]X_HYST_SCALE = 1.0Y_HYST_SCALE = 1.0Z_HYST_SCALE = 1.0TX_HYST_SCALE = 1.0TY_HYST_SCALE = 1.0TZ_HYST_SCALE = 1.0$-------------------------------------------------------------TFSISO[TFSISO_SCALES]X_TFSISO_SCALE = 1.0Y_TFSISO_SCALE = 1.0Z_TFSISO_SCALE = 1.0TX_TFSISO_SCALE = 1.0TY_TFSISO_SCALE = 1.0TZ_TFSISO_SCALE = 1.0$-----------------------------------------------------------FX_CURVE[FX_CURVE]{ x fx}-10.0 -2700.0-8.0 -2160.0-6.0 -1620.0-4.0 -1080.0-2.0 -540.00.0 0.02.0 540.04.0 1080.06.0 1620.08.0 2160.010.0 2700.0$-----------------------------------------------------------FY_CURVE[FY_CURVE]{ y fy}-10.0 -2700.0-8.0 -2160.0-6.0 -1620.0-4.0 -1080.0-2.0 -540.00.0 0.02.0 540.04.0 1080.06.0 1620.08.0 2160.010.0 2700.0$-----------------------------------------------------------FZ_CURVE[FZ_CURVE]{ z fz}-10.0 -2700.0-8.0 -2160.0-6.0 -1620.0-4.0 -1080.0-2.0 -540.00.0 0.0
25Dialog Box - F1 HelpExample Input Bushing Property File
2.0 540.04.0 1080.06.0 1620.08.0 2160.010.0 2700.0$-----------------------------------------------------------TX_CURVE[TX_CURVE]{ ax tx}-45.0 -36000.0-36.0 -28800.0-27.0 -21600.0-18.0 -14400.0-9.0 -7200.00.0 0.09.0 7200.018.0 14400.027.0 21600.036.0 28800.045.0 36000.0$-----------------------------------------------------------TY_CURVE[TY_CURVE]{ ay ty}-45.0 -36000.0-36.0 -28800.0-27.0 -21600.0-18.0 -14400.0-9.0 -7200.00.0 0.09.0 7200.018.0 14400.027.0 21600.036.0 28800.045.0 36000.0$-----------------------------------------------------------TZ_CURVE[TZ_CURVE]{ az tz}-45.0 -36000.0-36.0 -28800.0-27.0 -21600.0-18.0 -14400.0-9.0 -7200.00.0 0.09.0 7200.018.0 14400.027.0 21600.036.0 28800.045.0 36000.0$------------------------------------------------BUSHING_PARAMETERS [BUSHING_PARAMETERS] X_ALPHA = 0.5 X_BETA =20 X_GAMMA =-20 X_ZETA = 1.0 X_OMEGA =10.0
Adams/Car RideExample Input Bushing Property File
26
X_A =1.0 X_N =2.0 X_NUM =3.0,2.0,3.0 X_DEN =4.0,1.0,5.0,6.0 Y_ALPHA = 0.5 Y_BETA =20 Y_GAMMA =-20 Y_ZETA = 1.0 Y_OMEGA =10.0 Y_A =1.0 Y_N =2.0 Y_NUM =3.0,2.0,3.0 Y_DEN =4.0,1.0,5.0,6.0 Z_ALPHA = 0.5 Z_BETA =20 Z_GAMMA =-20 Z_ZETA = 1.0 Z_OMEGA =10.0 Z_A =1.0 Z_N =2.0 Z_NUM =3.0,2.0,3.0 Z_DEN =4.0,1.0,5.0,6.0 AX_ALPHA = 0.5 AX_BETA =20 AX_GAMMA =-20 AX_ZETA = 1.0 AX_OMEGA =10.0 AX_A =1.0 AX_N =2.0 AX_NUM =3.0,2.0,3.0 AX_DEN =4.0,1.0,5.0,6.0 AY_ALPHA = 0.5 AY_BETA =20 AY_GAMMA =-20 AY_ZETA = 1.0 AY_OMEGA =10.0 AY_A =1.0 AY_N =2.0 AY_NUM =3.0,2.0,3.0 AY_DEN =4.0,1.0,5.0,6.0 AZ_ALPHA = 0.5 AZ_BETA =20 AZ_GAMMA =-20 AZ_ZETA = 1.0 AZ_OMEGA =10.0 AZ_A =1.0 AZ_N =2.0 AZ_NUM =3.0,2.0,3.0 AZ_DEN =4.0,1.0,5.0,6.0
$--------------------------------------------------BUSHING_TEST_DATA
27Dialog Box - F1 HelpExample Input Bushing Property File
[BUSHING_TEST_DATA]
$--------------------------------------------------BUSHING_SCALE_DATA[BUSHING_SCALE_DATA]
{amplitude frequency cdyn phase}
0.100000 1.000000 392.000000 1.900000
0.100000 2.000000 393.000000 3.800000
0.100000 3.000000 393.000000 4.800000
... continue
0.100000 40.000000 773.000000 4.700000
0.500000 1.000000 389.000000 2.800000
0.500000 2.000000 386.000000 4.100000
0.500000 3.000000 385.000000 5.800000
... continue
0.500000 40.000000 734.000000 4.800000
1.000000 1.000000 379.000000 3.100000
1.000000 2.000000 377.000000 4.800000
1.000000 3.000000 378.000000 6.900000
... continue
1.000000 40.000000 700.000000 4.700000
{amplitude frequency cdyn phase}
0.100000 1.000000 1.000000 1.000000
0.100000 2.000000 1.000000 1.000000
0.100000 3.000000 1.000000 1.000000
... continue
0.100000 40.000000 1.000000 1.000000
0.500000 1.000000 1.000000 1.000000
0.500000 2.000000 1.000000 1.000000
0.500000 3.000000 1.000000 1.000000
... continue
0.500000 40.000000 1.000000 1.000000
1.000000 1.000000 1.000000 1.000000
Adams/Car RideExample Input Bushing Property File
28
1.000000 2.000000 1.000000 1.000000
1.000000 3.000000 1.000000 1.000000
... continue
1.000000 40.000000 1.000000 1.000000
29Dialog Box - F1 HelpExample Output Bushing Property File
Example Output Bushing Property File The following is an example output bushing property file.
$-----------------------------------------------------MDI_HEADER [MDI_HEADER] FILE_TYPE = 'gbu' FILE_VERSION = 2.0 FILE_FORMAT = 'ASCII' $-----------------------------------------------------UNITS [UNITS] LENGTH = 'mm' FORCE = 'newton' ANGLE = 'degrees' MASS = 'kg' TIME = 'second' $-----------------------------------------------------GENERAL [GENERAL] DEFINITION = '.aride.attachment.ac_general_bushing' BUSHING_COORDINATE = 'z' BUSHING_SHAPE = 0BUSHING_COUPLING = 1$------------------------------------------------------------DAMPING[DAMPING] X_LOSS_ANGLE = 0.0 Y_LOSS_ANGLE = 0.0 Z_LOSS_ANGLE = 0.0 TX_LOSS_ANGLE = 0.0 TY_LOSS_ANGLE = 0.0 TZ_LOSS_ANGLE = 0.0$------------------------------------------------------------PRELOAD[PRELOAD] X_PRELOAD = 0.0 Y_PRELOAD = 0.0 Z_PRELOAD = 0.0 TX_PRELOAD = 0.0 TY_PRELOAD = 0.0 TZ_PRELOAD = 0.0$-------------------------------------------------------------OFFSET[OFFSET] X_OFFSET = 0.0 Y_OFFSET = 0.0 Z_OFFSET = 0.0 TX_OFFSET = 0.0 TY_OFFSET = 0.0 TZ_OFFSET = 0.0$-------------------------------------------------------------SPLINE[SPLINE_SCALES]FX_CURVE_SCALE = 1.0FY_CURVE_SCALE = 1.0FZ_CURVE_SCALE = 1.0TX_CURVE_SCALE = 1.0TY_CURVE_SCALE = 1.0TZ_CURVE_SCALE = 1.0$----------------------------------------------------------BOUC-WEN
Adams/Car RideExample Output Bushing Property File
30
[HYST_SCALES]X_HYST_SCALE = 1.0Y_HYST_SCALE = 1.0Z_HYST_SCALE = 1.0TX_HYST_SCALE = 1.0TY_HYST_SCALE = 1.0TZ_HYST_SCALE = 1.0$-------------------------------------------------------------TFSISO[TFSISO_SCALES]X_TFSISO_SCALE = 1.0Y_TFSISO_SCALE = 1.0Z_TFSISO_SCALE = 1.0TX_TFSISO_SCALE = 1.0TY_TFSISO_SCALE = 1.0TZ_TFSISO_SCALE = 1.0
$-----------------------------------------------------------FX_CURVE[FX_CURVE]{ x fx}-10.0 -2700.0-8.0 -2160.0-6.0 -1620.0-4.0 -1080.0-2.0 -540.00.0 0.02.0 540.04.0 1080.06.0 1620.08.0 2160.010.0 2700.0$-----------------------------------------------------------FY_CURVE[FY_CURVE]{ y fy}-10.0 -2700.0-8.0 -2160.0-6.0 -1620.0-4.0 -1080.0-2.0 -540.00.0 0.02.0 540.04.0 1080.06.0 1620.08.0 2160.010.0 2700.0$-----------------------------------------------------------FZ_CURVE[FZ_CURVE]{ z fz}-10.0 -2700.0-8.0 -2160.0-6.0 -1620.0-4.0 -1080.0-2.0 -540.00.0 0.02.0 540.0
31Dialog Box - F1 HelpExample Output Bushing Property File
4.0 1080.06.0 1620.08.0 2160.010.0 2700.0$-----------------------------------------------------------TX_CURVE[TX_CURVE]{ ax tx}-45.0 -36000.0-36.0 -28800.0-27.0 -21600.0-18.0 -14400.0-9.0 -7200.00.0 0.09.0 7200.018.0 14400.027.0 21600.036.0 28800.045.0 36000.0$-----------------------------------------------------------TY_CURVE[TY_CURVE]{ ay ty}-45.0 -36000.0-36.0 -28800.0-27.0 -21600.0-18.0 -14400.0-9.0 -7200.00.0 0.09.0 7200.018.0 14400.027.0 21600.036.0 28800.045.0 36000.0$-----------------------------------------------------------TZ_CURVE[TZ_CURVE]{ az tz}-45.0 -36000.0-36.0 -28800.0-27.0 -21600.0-18.0 -14400.0-9.0 -7200.00.0 0.09.0 7200.018.0 14400.027.0 21600.036.0 28800.045.0 36000.0$------------------------------------------------BUSHING_PARAMETERS [BUSHING_PARAMETERS] X_ALPHA = 0.5 X_BETA =20 X_GAMMA =-20 X_ZETA = 1.0 X_OMEGA =10.0 X_A =1.0
Adams/Car RideExample Output Bushing Property File
32
X_N =2.0 X_NUM =3.0,2.0,3.0 X_DEN =4.0,1.0,5.0,6.0 Y_ALPHA = 0.5 Y_BETA =20 Y_GAMMA =-20 Y_ZETA = 1.0 Y_OMEGA =10.0 Y_A =1.0 Y_N =2.0 Y_NUM =3.0,2.0,3.0 Y_DEN =4.0,1.0,5.0,6.0 Z_ALPHA = 0.5 Z_BETA =20 Z_GAMMA =-20 Z_ZETA = 1.0 Z_OMEGA =10.0 Z_A =1.0 Z_N =2.0 Z_NUM =3.0,2.0,3.0 Z_DEN =4.0,1.0,5.0,6.0 AX_ALPHA = 0.5 AX_BETA =20 AX_GAMMA =-20 AX_ZETA = 1.0 AX_OMEGA =10.0 AX_A =1.0 AX_N =2.0 AX_NUM =3.0,2.0,3.0 AX_DEN =4.0,1.0,5.0,6.0 AY_ALPHA = 0.5 AY_BETA =20 AY_GAMMA =-20 AY_ZETA = 1.0 AY_OMEGA =10.0 AY_A =1.0 AY_N =2.0 AY_NUM =3.0,2.0,3.0 AY_DEN =4.0,1.0,5.0,6.0 AZ_ALPHA = 0.5 AZ_BETA =20 AZ_GAMMA =-20 AZ_ZETA = 1.0 AZ_OMEGA =10.0 AZ_A =1.0 AZ_N =2.0 AZ_NUM =3.0,2.0,3.0 AZ_DEN =4.0,1.0,5.0,6.0$-------------------------------------BUSHING_IDENTIFICATION_DATA[BUSHING_IDENTIFICATION_DATA]
{amplitude frequency cdyn phase}
0.100000 1.000000 404.863819 1.243071
33Dialog Box - F1 HelpExample Output Bushing Property File
$--------------------------------------------------BUSHING_TEST_DATA[BUSHING_TEST_DATA]
0.100000 2.000000 399.691551 2.618614
0.100000 3.000000 388.455029 4.605679
... continue
0.100000 40.000000 713.285910 6.099968
0.500000 1.000000 404.772004 1.302907
0.500000 2.000000 399.309176 2.830528
0.500000 3.000000 389.903747 4.774778
... continue
0.500000 40.000000 716.810500 6.126563
1.000000 1.000000 404.777324 1.347649
1.000000 2.000000 399.296585 3.024592
1.000000 3.000000 390.207932 5.272207
... continue
1.000000 40.000000 700.288389 6.281555
{amplitude frequency cdyn phase}
0.100000 1.000000 392.000000 1.900000
0.100000 2.000000 393.000000 3.800000
0.100000 3.000000 393.000000 4.800000
... continue
0.100000 40.000000 773.000000 4.700000
0.500000 1.000000 389.000000 2.800000
0.500000 2.000000 386.000000 4.100000
0.500000 3.000000 385.000000 5.800000
... continue
0.500000 40.000000 734.000000 4.800000
1.000000 1.000000 379.000000 3.100000
1.000000 2.000000 377.000000 4.800000
1.000000 3.000000 378.000000 6.900000
... continue
1.000000 40.000000 700.000000 4.700000
Adams/Car RideExample Output Bushing Property File
34
$-------------------------------------------------BUSHING_SCALE_DATA[BUSHING_SCALE_DATA]
{amplitude frequency cdyn phase}
0.100000 1.000000 1.000000 1.000000
0.100000 2.000000 1.000000 1.000000
0.100000 3.000000 1.000000 1.000000
... continue
0.100000 40.000000 1.000000 1.000000
0.500000 1.000000 1.000000 1.000000
0.500000 2.000000 1.000000 1.000000
0.500000 3.000000 1.000000 1.000000
... continue
0.500000 40.000000 1.000000 1.000000
1.000000 1.000000 1.000000 1.000000
1.000000 2.000000 1.000000 1.000000
1.000000 3.000000 1.000000 1.000000
... continue
1.000000 40.000000 1.000000 1.000000
35Dialog Box - F1 HelpExample Output Hydromount Property File
Example Output Hydromount Property File The following is an example output hydromount property file. We left out the data for frequencies 4 - 39 Hz.
$-----------------------------------------------------MDI_HEADER [MDI_HEADER] FILE_TYPE = 'hbu' FILE_VERSION = 1.0 FILE_FORMAT = 'ASCII' $-----------------------------------------------------UNITS [UNITS] LENGTH = 'mm' FORCE = 'newton' ANGLE = 'degrees' MASS = 'kg' TIME = 'second' $-----------------------------------------------------GENERAL [GENERAL] DEFINITION = '.ride.attachment.ac_hydro_bushing' HYDRO_COORDINATE = 'z' BUSHING_PROPERTY_FILE = '<ride>/bushings.tbl/mdi_0001.bus' SUPER_IMPOSE_BUSHING = 'off' $----------------------------------------------------HYDRO_PARAMETERS [HYDRO_PARAMETERS] RUBBER_STIFFNESS = 406.544598 RUBBER_DAMPING = 0.29298822 COUPLING_STIFFNESS = 282.526692 COUPLING_STIFFNESS_DECLINING = 0.071232 LINEAR_FLUID_DAMPING = 1.10642663 QUADRATIC_FLUID_DAMPING = 0.01834762 EFFECTIVE_FLUID_MASS = 51.416425 CLEARANCE = 0.0 $----------------------------------------------------HYDRO_IDENTIFICATION_DATA [HYDRO_IDENTIFICATION_DATA]
{amplitude frequency cdyn phase}
0.100000 1.000000 404.863819 1.243071
0.100000 2.000000 399.691551 2.618614
0.100000 3.000000 388.455029 4.605679
... continue
0.100000 40.000000 713.285910 6.099968
0.500000 1.000000 404.772004 1.302907
0.500000 2.000000 399.309176 2.830528
0.500000 3.000000 389.903747 4.774778
... continue
0.500000 40.000000 716.810500 6.126563
Adams/Car RideExample Output Hydromount Property File
36
$----------------------------------------------------HYDRO_TEST_DATA [HYDRO_TEST_DATA]
$OBJECTIVE_FUNCTION = 1.5051 $INTEGRATOR_ERROR = 0.0050 $STEADY_STATE_ERROR = 0.0100 $CONVERGENCE_TOLERANCE = 0.0050 $*** OPTIMIZATION ABORDED ***
1.000000 1.000000 404.777324 1.347649
1.000000 2.000000 399.296585 3.024592
1.000000 3.000000 390.207932 5.272207
... continue
1.000000 40.000000 700.288389 6.281555
{amplitude frequency cdyn phase}
0.100000 1.000000 392.000000 1.900000
0.100000 2.000000 393.000000 3.800000
0.100000 3.000000 393.000000 4.800000
... continue
0.100000 40.000000 773.000000 4.700000
0.500000 1.000000 389.000000 2.800000
0.500000 2.000000 386.000000 4.100000
0.500000 3.000000 385.000000 5.800000
... continue
0.500000 40.000000 734.000000 4.800000
1.000000 1.000000 379.000000 3.100000
1.000000 2.000000 377.000000 4.800000
1.000000 3.000000 378.000000 6.900000
... continue
1.000000 40.000000 700.000000 4.700000
37Dialog Box - F1 HelpFull-Vehicle Analysis: ARIDE_FOUR_POST_TESTRIG
Full-Vehicle Analysis: ARIDE_FOUR_POST_TESTRIGRide -> Full-Vehicle Analysis -> Four-Post Test Rig
Sets up a full-vehicle analysis.
For the option: Do the following:
Full-Vehicle Assembly Select the full-vehicle assembly you want to analyze.
Tips on Entering File Names in Text Boxes.
Output Prefix Enter a string that specifies the Analysis Output Name. The string can contain only alphanumeric characters and underscores (_).
End Time Specify the time, in seconds, at which the analysis ends.
Mode of Simulation Select Interactive, Background, or Files_only.
Basis for Number of Output Steps
Select one of the following:
• number of output steps - Set the total number of outputs (per individual output variable). These will be equally spaced from time = zero to time = End Time.
• output interval - Set the time interval between outputs. Adams/Car Ride calculates the total number of outputs in terms of this number.
• output frequency - Set the time frequency at which outputs are stored. Adams/Car Ride calculates the total number of outputs in terms of this number. We give you this option because it is often easier to think in terms of frequency than in terms of the total number of outputs or the interval between outputs.
• min. number of outputs per input - This option applies only when you select a swept-sine input. Using this option will set the output frequency to be equal to the number you select in the Target Value For Basis text box multiplied by the highest frequency of the frequency sweep. This number should ideally range from ten to twenty, but never be less than six.
To prevent errors from aliasing, the frequency of outputs should be at least six times that of the highest input frequency that will affect outputs of interest. A factor of ten is much better, and a factor of 20 is very good.
Target Value for Basis Enter the number corresponding to your selection above for Basis for Number of Output Steps. The units for this text box change to reflect the selection you made above.
Adams/Car RideFull-Vehicle Analysis: ARIDE_FOUR_POST_TESTRIG
38
Note: The following four text boxes display values that describe the number of outputs in each of the options you can select in Basis for Number of Output Steps. Different information from the simulation set-up is needed to fill-in these text boxes. A value will appear in a text box as soon as you provide enough information for Adams/Car Ride to calculate its value. Note that these numbers might not be exactly the same as your selection in Target Value for Basis. This is because the values must be set so that an integral number of outputs is obtained.
Number of Output Steps See Note, above.
Output Interval See Note, above.
Output Frequency See Note, above.
The following text box is displayed only when you set Input Source to swept sine.
Min. Number of Output Steps Per Input
See Note, above.
Actuation Type Select one of the following:
• displacement
• velocity
• acceleration
• force
Your selection determines the type of control that prescribes the behavior of the test-rig actuators. Note that sometimes an actuation type either does not apply (that is, it doesn't make sense physically given the vehicle model) or is not supported depending on other settings you choose. For example, if you set Actuation Type to force, Adams/Car Ride automatically sets Input Locations to wheel spindles. This is because the other option for Input Locations, beneath tires, does not apply for Adams-compatible tire models that are supported in Adams/Car Ride. Because the tire carcass itself is not modeled as a physical body, a force cannot be applied to it.
For the option: Do the following:
39Dialog Box - F1 HelpFull-Vehicle Analysis: ARIDE_FOUR_POST_TESTRIG
Input Source Select one of the following:
• arbitrary solver functions
• road profiles
• swept sine
• RPC files
Your selection determines the type of control function that prescribes the behavior of the test-rig actuators with the selected Actuation Type. The selections depend on the Actuation Type. For example, of the four Actuation Types, you can always select arbitrary solver functions and swept sine as control functions. However, road profile inputs are only supported when Actuation Type is set to displacement.
Learn about RPC III Format
Input Locations Select one of the following:
• beneath tires - The actuators will excite the vehicle by contact with the tires.
• wheel spindles - The actuators will excite the vehicle by control directly at the wheel spindles.
If you set Actuation Type to force, only the wheel spindles option is applicable.
If you set Input Source to swept sine, Adams/Car Ride displays the following options:
Start Frequency Enter the frequency of the sinusoidal input at time = zero. The swept-sine input sweeps out the frequencies from Start Frequency to End Frequency linearly from time = zero to time = End Time. The Start Frequency can be higher than the End Frequency.
End Frequency Enter the frequency of the sinusoidal input at time = End Time. The swept-sine input sweeps out the frequencies from Start Frequency to End Frequency linearly from time = zero to time = End Time. The Start Frequency can be higher than the End Frequency.
The label on the following text box changes to reflect the selection you made for Actuation Type. For example, if you set it to acceleration, the label changes to Acceleration Amplitude.
Displacement Amplitude Select the amplitude of the sinusoidal control for the swept sine inputs. The name and units choices for this text box change to reflect your selection for Actuation Type.
For the option: Do the following:
Adams/Car RideFull-Vehicle Analysis: ARIDE_FOUR_POST_TESTRIG
40
Excitation Mode Your selection determines the relative phase of the test-rig actuators during a swept-sine simulation.
Select one of the following:
• heave - All actuators are in phase, thus causing a heave-type motion in the vehicle.
• pitch - The left and right actuators are in phase, but the rear actuators lag those of the front by 180 degrees, thus causing a pitch-type motion in the vehicle.
• roll - The front and rear actuators are in phase on each side of the vehicle, but the actuators on the right lag those on the left by 180 degrees, thus causing a roll-type motion in the vehicle.
• warp - The left-front and right-rear actuators are in phase. The right-front and left-rear actuators are also in phase, but they lag the left-front and right-rear actuators by 180 degrees, therefore causing a warp-type motion in the vehicle.
Active Actuators Specify which actuators are active during a swept-sine simulation. Inactive actuators remain stationary. The options depend on your selection for Excitation Mode. For example, if you set Excitation Mode to heave, you can set all actuators to be active, front or rear, right or left, or any particular one. However, if you set Excitation Mode to warp, all actuators must be active because a warp simulation has little meaning otherwise.
If you set Input Source to arbitrary solver functions, Adams/Car Ride displays the following options:
Note: Set each of the following text boxes to an Adams/Solver-function expression. You can enter the expression directly to create the function in the Function Builder. (When you exit the Function Builder, Adams/Car Ride automatically enters the expression you created into the appropriate text box.)
Enter 0 if:
• You want no motion of an actuator if the Actuation Type is kinematic.
• If you want the actuator to apply zero force at the spindle if you set Actuation Type to force. (In this case, the wheel associated with that actuator is not influenced by the test rig at all: it is free to fall.)
Left Front See Note, above.
Right Front See Note, above.
Left Rear See Note, above.
Right Rear See Note, above.
For the option: Do the following:
41Dialog Box - F1 HelpFull-Vehicle Analysis: ARIDE_FOUR_POST_TESTRIG
Solver Function Units Select the units for your Adams/Solver function expression.
The options have dimensions consistent with the setting in Actuation Type. Solver functions that you enter should return a numerical value expressed in the units of the Solver Function Units setting. For example, suppose the Actuation Type is set to acceleration and Solver Function Units is set to g's. Your solver functions should evaluate to a numerical value expressed in g's. This is true regardless of the setting in the Setting/Units menu in Adams/View.
If you set Input Source to road profiles, Adams/Car Ride displays the following option:
Set Up Road Profiles Select to display the dialog box Road-Profile Setup: ARIDE_FOUR_POST_TESTRIG, where you can set the road parameters.
Create Analysis Log File Select if you want Adams/Car to write information about the assembled model and analysis to an Analysis Log File.
Select to display a dialog box where you can add multi-line comments to any entity, to describe its purpose and function. Adams/Car Ride displays different comments dialog boxes, depending on the entity type for which you want to record comments:
• If recording comments for modeling entities in Standard Interface, Adams/Car Ride displays the Entity Comments dialog box.
• If recording comments for any other entity type, Adams/Car Ride displays the Modify Comment dialog box.
Learn more about Recording Comments.
For the option: Do the following:
Adams/Car RideFull-Vehicle Vibration Analysis: ARIDE_FOUR_POST_TESTRIG
42
Full-Vehicle Vibration Analysis: ARIDE_FOUR_POST_TESTRIGRide -> Full-Vehicle Vibration Analysis -> Four-Post Test Rig
Sets up a full-vehicle vibration analysis. To use this dialog box, you must have a license for Adams/Vibration. If you have access to the Adams/Vibration plugin, it loads when the Adams/Ride plugin loads.
For the option: Do the following:
Full-Vehicle Assembly Select the full-vehicle assembly you want to analyze.
Tips on Entering File Names in Text Boxes.
Output Prefix Enter a string that specifies the Analysis Output Name. The string can contain only alphanumeric characters and underscores (_).
Input Location Adams/Car Ride automatically creates vibration input channels. Depending on the actuation type chosen (below), the channels drive each pad of the rig with a kinematic input below each tire contact patch, to enable you to identify the vehicle response to road roughness inputs, or they drive wheel centers with a force input. At the same time, Adams/Car Ride automatically creates vibration output channels to enable you to analyze the response at key points on the vehicle, such as the wheel centers and strut (damper) top mounts. In addition, you can add vibration output channels to specific locations on your model.
Input Direction Adams/Car Ride creates vibration input channels (actuators) that act in the vertical direction (only).
Actuation Type Select the type of input the kinematic vibration actuators should provide in the test rig. As typical road spectra are approximately flat when plotted against velocity, we recommend the velocity input. However, the available options are:
• displacement
• velocity
• acceleration
• force
43Dialog Box - F1 HelpFull-Vehicle Vibration Analysis: ARIDE_FOUR_POST_TESTRIG
Actuator properties (for Left Front, Right Front, Left Rear, and Right Rear)
Specify the magnitude and phase (in degrees) of the input at each corner of the vehicle, in the units of the excitation quantities you selected for Actuation Type. By setting these values, you define the mode of excitation of the vehicle during the vibration analysis.
Select one of the following to define the actuators properties:
• Swept Sine. See Entering Swept Sine Function for available options.
• PSD. (Power Spectral Density). See Entering PSD Function for available options.
• User. (User-Defined Function). See Entering a User-Defined function for available options.
For example:
• If you choose swept sine excitational tire contact patches for all wheels, and set both front inputs to a magnitude of 1.0 and everything else to zero, you will excite the front axle only.
• If you set all magnitudes to 1.0, and the left channels to a phase of zero, but the right channels to a phase of 180 degrees, you will excite the vehicle with rolling motion that excites the left and right side with equal and opposite displacement or force (depending on whether you selected a kinematic or a force excitation above).
These values will have no influence on any transfer-function analyses, which present the output per unit input for every possible pair of input channel and output channel. The values will, however, influence frequency-response analyses, which present the system output that occurs because of the sum of all inputs (and the system transfer functions), considering both the phase and magnitude of those inputs.
Plot Actuator Select to open the Actuator Preview Plot dialog box where you can see the plot of your actuator without running a simulation.
Only available when modifying an input channel.
For the option: Do the following:
Adams/Car RideFull-Vehicle Vibration Analysis: MKB matrices export
44
Full-Vehicle Vibration Analysis: MKB matrices export Full-Vehicle A2N setup: Four Poster_Testrig
Sets up a full-vehicle A2N analysis. To use this dialog box, you must have a license for Adams/Vibration. If you have access to the Adams/Vibration plugin, it loads when the Adams/Car Ride plugin loads.
For the option: Do the following:
Full-Vehicle Assembly Select the full-vehicle assembly you want to analyze.
Analysis name Enter a string that specifies the Analysis Output Name. The string can contain only alphanumeric characters and underscores (_).
Input Location Adams/Car Ride automatically creates A2N input channels. Currently only Force is available as Actuation Type, so they are applied to drive wheel centers as a force input. At the same time, Adams/Car Ride automatically creates vibration output channels to enable you to analyze the response at key points on the vehicle, such as the wheel centers and strut (damper) top mounts. No other A2N output channels can currently be created in user specified locations on the model.
Input Direction Adams/Car Ride creates vibration input channels (actuators) that act in the vertical direction (only).
Adams/Car RideFull-Vehicle Vibration Analysis: MKB matrices export
45
Click on Ok button, the A2N MKB matrices export dialog box is displayed.
Actuation Type Select the type of input the actuators should provide in the test rig. Currently only one option is available:
• force
Actuator properties (for Left Front, Right Front, Left Rear, and Right Rear)
Specify the magnitude and phase (in degrees) of the input at each corner of the vehicle, in the units of the excitation quantities you selected for Actuation Type. By setting these values, you define the mode of excitation of the vehicle during the A2N analysis.
On the input channel an actuator force (swept-sine type) is applied into Nastran: each actuator is described by the direction (X, Y, Z), mode (translational = force or rotational = torque), force magnitude and phase angle
• Swept sine defines a constant amplitude sine function being applied to the model.
Due to the different marker orientation in correspondence of the wheel centers between left and right side (the forces are oriented as wheel center markers):
• If you choose swept sine for all wheels, and set both front inputs to a magnitude of 1.0 and everything else to zero, you will excite upward on the left side and downward on the right side - you will excite the vehicle with rolling motion that excites the left and right side with equal and opposite force
• If you set all magnitudes to 1.0, and the left channels to a phase of zero, but the right channels to a phase of 180 degrees, you will excite the full vehicle upward.
For the option: Do the following:
Adams/Car RideGSE Damper Code Import
46
GSE Damper Code Import
Modify GSE Damper dialog box -> select
Imports code for GSE Damper.
For the option: Do the following:
Library to be imported Enter the name of the RealTime Workshop (RTW) library you want to import. On Windows, this is likely to be a file with the extension .dll. On most UNIX platforms, this file will have a .so extension, and on HP-UX it will have a .sl extension.
Adams/Car Ride copies this file from the specified location within your file system to the gse_damper.tbl directory of your default writable database.
Adams/Car Ride opens this file during the import process and analyzes it for parameters that you can change. It then writes these parameters to a property file as specified in the Property Files name text box.
Property file name Enter a new name for the property file Adams/Car Ride automatically generates when it imports the library. By default, Adams/Car Ride stores this property file in the gse_damper.tbl directory of your default writable database.
When you exit this dialog box, this text box will be automatically populated with the new property file.
Notes: • If the dialog box does not close when you select OK, select Cancel. This does not affect the importing of the library or the generation of the property file.
• At runtime, when Adams/Car Ride reads the property files, it copies the library to your home directory for use with Adams/Solver.
47Dialog Box - F1 HelpHydromount-Parameter Identification
Hydromount-Parameter IdentificationRide -> Tools -> Hydromount-Parameter Identification
Identifies the parameters of a hydromount model for given measurements of dynamic stiffness and loss angle dependent on frequency. Learn about Hydromount-Parameter Identification Tool.
For the option: Do the following:
Input File Name Enter the name of a hydromount input file. See About Input Hydromount Property Files.
Load Select to load an input file.
Input Parameters:
Calculate Frequency Response
Select to calculate the frequency response data with the current input parameters that are displayed in the text boxes. You can manually change those parameters and use this button to see the influence on the frequency response.
Error Control
Integrator Error Enter the allowed error of the states of the hydromount during numerical integration.
Steady-State Error Enter the allowed difference for the dynamic stiffness and loss angle between subsequent cycles.
Convergence Tolerance Enter the tolerance for which the objective function is considered converged.
Max Optimizer Loops Enter the maximum number of iterations to find the optimum.
Go Select to start the identification process.
Stop Select to stop the identification process.
Plot Displays the frequency response of the model, the dynamic stiffness in the plot named Cdyn and the loss angle in the plot named Phase.
Data Displays the input file and the frequency response data.
Output File Name -
Save Select to save an output file in property file format. See an Example Output Hydromount Property File.
Adams/Car RideISO Ride Index
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ISO Ride IndexRide -> Full-Vehicle Vibration Analysis -> ISO Ride Index
Learn about the ISO Ride Index.
Define the parameters for ISO Ride Index.
For the option: Do the following:
Ride Index This is a read only field. Adams/Car Ride will display the calculated output Overall/Point Vibration Total Value here.
Output Select the appropriate output you want to calculate: OVTV, Feet PVTV, Seat PVTV and Back PVTV.
Analysis Select the appropriate analysis for calculating its Ride Index.
Depending on your output option selection, the following four tabs will be disabled or enabled. The Overall tab is enabled only for calculating OVTV output.
Define acceleration requests, scaling factors and ISO weighting curves (for driver/passenger Feet, Seat and Back locations)
• Specify the acceleration result set components for X, Y and Z directions at driver/passenger Feet, Seat and Back locations.
• Specify the directional and overall scaling factors for each of these location and direction.
• Specify the ISO frequency weighting curves for each of these locations and directions.
49Dialog Box - F1 HelpModify Frequency-Dependent Bushing
Modify Frequency-Dependent BushingRight-click component -> Modify
Learn About the Bushing Model.
For the option: Do the following:
Bushing Enter the database name of a hydro bushing.
Linear Preload Enter the initial translational force loading on the bushing, defined along the x-, y-, and z-axes of the bushing. The preload is always superimposed on the hydro force component.
Torsional Preload Enter the initial torsional force loading on the bushing, defined about the x-, y-, and z-axes of the bushing.
Linear Offset Enter the initial translational displacement of the bushing, defined along the x-, y-, and z-axes of the bushing.
Rotational Offset Enter the initial rotational displacement of the bushing, defined about the x-, y-, and z-axes of the bushing.
Property File Specify the property file that contains all static spline forces and all loss angles for the six force components.
When you modify component pairs (brothers), Adams/Car Ride enables the following option: (When you modify a single component, this option is disabled because a single component is by nature asymmetric.)
Symmetric Select one of the following:
• yes - Modify properties of both components in a pair.
• no - Only modify properties of the selected component.
Adams/Car RideModify Frequency-Dependent Bushing
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Select to display a dialog box where you can add multi-line comments to any entity, to describe its purpose and function. Adams/Car Ride displays different comments dialog boxes, depending on the entity type for which you want to record comments:
• If recording comments for modeling entities in Standard Interface, Adams/Car Ride displays the Entity Comments dialog box.
• If recording comments for any other entity type, Adams/Car Ride displays the Modify Comment dialog box.
Learn more about Recording Comments. Select to view property file information. By default, your template-based
product displays this information in the Information window, but you can choose to display the information in a text editor.
Learn about:
• Working with the Information Window
• Editing Files Using a Text Editor
For the option: Do the following:
51Dialog Box - F1 HelpModify GSE Damper
Modify GSE DamperRight-click component -> Modify
Modifies a GSE Damper.
For the option: Do the following:
Damper Enter the database name of a GSE damper.
Property File Select the property file (See Property Files for more information) to be used or use the import utility
(see below).
Symmetric Select one of the following:
• yes - Modify properties of both components in a pair.
• no - Only modify properties of the selected component.
Select to display a dialog box where you can add multi-line comments to any entity, to describe its purpose and function. Adams/Car Ride displays different comments dialog boxes, depending on the entity type for which you want to record comments:
• If recording comments for modeling entities in Standard Interface, Adams/Car Ride displays the Entity Comments dialog box.
• If recording comments for any other entity type, Adams/Car Ride displays the Modify Comment dialog box.
Learn more about Recording Comments.
Select to display the GSE Damper Code Import dialog box.
Select to view property file information. By default, your template-based product displays this information in the Information window, but you can choose to display the information in a text editor.
Learn about:
• Working with the Information Window
• Editing Files Using a Text Editor
Adams/Car RideModify General Frequency Dependent Element
52
Modify General Frequency Dependent ElementDefine the parameters for a General FD Element
For the option: Do the following:
Bushing Enter the database name of a hydro bushing.
Property File Specify the property file that contains all static spline forces and all loss angles for the six force components.
Desired Components Select the desired components for which you want to modify the general frequency dependent element.
Type Select the appropriate type you want to modify:
Pfeffer Linear, Simple FD, Simple FD-Bushing, and General.
Preload Enter the initial translational force loading on the bushing, defined along the x-, y-, and z-axes of the bushing. The preload is always superimposed on the hydro force component.
Symmetric Select one of the following:
• yes - Modify properties of both components in a pair.
• no - Only modify properties of the selected component.
When you modify component pairs (brothers), Adams/Car Ride enables the following option: (When you modify a single component, this option is disabled because a single component is by nature asymmetric.)
Select to display a dialog box where you can add multi-line comments to any entity, to describe its purpose and function. Adams/Car Ride displays different comments dialog boxes, depending on the entity type for which you want to record comments:
• If recording comments for modeling entities in Standard Interface, Adams/Car Ride displays the Entity Comments dialog box.
• If recording comments for any other entity type, Adams/Car Ride displays the Modify Comment dialog box.
Learn more about Recording Comments.
Select to view property file information. By default, your template-based product displays this information in the Information window, but you can choose to display the information in a text editor.
Learn about:
• Working with the Information Window
• Editing Files Using a Text Editor
53Dialog Box - F1 HelpModify Hydro Bushing
Modify Hydro BushingRight-click component -> Modify
Modifies a hydro bushing. Learn more About Hydromount Models.
For the option: Do the following:
Bushing Enter the database name of a hydro bushing.
Orient using Select one of the following:
• Euler Angles
• Direction Vectors
If you select Euler Angles, Adams/Car Ride enables the following option:
Euler Angles Enter the three euler angle values that define the hydromount's orientation.
If you select Direction Vectors, Adams/Car Ride enables the following two options:
X Vector Enter the x, y, and z values that define the direction of the x-vector along which the hydromount will be oriented.
Z Vector Enter the x, y, and z values that define the direction of the z-vector along which the hydromount will be oriented.
Linear Preload Enter the initial translational force loading on the bushing, defined along the x-, y-, and z-axes of the bushing. The preload is always superimposed to the hydro force component.
Torsional Preload Enter the initial torsional force loading on the bushing, defined about the x-, y-, and z-axes of the bushing.
Linear Offset Enter the initial translational displacement of the bushing, defined along the x-, y-, and z-axes of the bushing. The displacement offset dz0 in the hydro_force is copied from this linear offset.
Rotational Offset Enter the initial rotational displacement of the bushing, defined about the x-, y-, and z-axes of the bushing.
Property File Specify the property file that contains the hydro force parameter and the name of the bushing property file.
Symmetric Enabled when you modify component pairs (or brothers):
• yes - Modify properties of both components in a pair.
• no - Only modify properties of the selected component.
When you modify a single component, this option is disabled because a single component is by nature assymetric.
Adams/Car RideModify Hydro Bushing
54
Property File Select to view property file information. By default, your template-based product displays this information in the Information window, but you can choose to display the information in a text editor.
Learn about:
• Working with the Information Window
• Editing Files Using a Text Editor
Apply Property File Select to cause the UDE instance to match the property file. (Adams/Car Ride automatically performs this operation before a simulation.)
Bushing Property Select to view property file information. By default, your template-based product displays this information in the Information window, but you can choose to display the information in a text editor.
Learn about:
• Working with the Information Window
• Editing Files Using a Text Editor
Superimpose Bushing Select to switch the superimposition of the bushing force component on or off.
Select to display a dialog box where you can add multi-line comments to any entity, to describe its purpose and function. Adams/Car Ride displays different comments dialog boxes, depending on the entity type for which you want to record comments:
• If recording comments for modeling entities in Standard Interface, Adams/Car Ride displays the Entity Comments dialog box.
• If recording comments for any other entity type, Adams/Car Ride displays the Modify Comment dialog box.
Learn more about Recording Comments.
For the option: Do the following:
55Dialog Box - F1 HelpModify Single Component Frequency Dependent Element
Modify Single Component Frequency Dependent ElementDefine the parameters for a Single Component FD Element
For the option: Do the following
Single component FD element
Enter the database name of a hydro bushing.
Property File Specify the property file that contains all static spline forces and all loss angles for the force component.
Type Select the appropriate type you want to modify:
Pfeffer Linear, Simple FD, Simple FD-Bushing, and General.
Preload Enter the initial translational force loading on the bushing, defined along the x-, y-, and z-axes of the bushing. The preload is always superimposed on the hydro force component.
Symmetric Select one of the following:
• yes - Modify properties of both components in a pair.
• no - Only modify properties of the selected component.
When you modify component pairs (brothers), Adams/Car Ride enables the following option: (When you modify a single component, this option is disabled because a single component is by nature asymmetric.)
Select to display a dialog box where you can add multi-line comments to any entity, to describe its purpose and function. Adams/Car Ride displays different comments dialog boxes, depending on the entity type for which you want to record comments:
• If recording comments for modeling entities in Standard Interface, Adams/Car Ride displays the Entity Comments dialog box.
• If recording comments for any other entity type, Adams/Car Ride displays the Modify Comment dialog box.
Learn more about Recording Comments.
Select to view property file information. By default, your template-based product displays this information in the Information window, but you can choose to display the information in a text editor.
Learn about:
• Working with the Information Window
• Editing Files Using a Text Editor
Adams/Car RidePerform Vibration Analysis
56
Perform Vibration AnalysisRide -> Full-Vehicle Vibration Analysis -> Four-Post Test Rig -> OK
Sets up a vibration full-vehicle analysis. To use this dialog box, you must have a license for Adams/Vibration. If you have access to the Adams/Vibration plugin, then it will have been loaded when the Adams/Ride plugin was loaded.
For the option: Do the following:
Tips on Entering File Names in Text Boxes
New Vibration Analysis/Vibration Analysis
Specify whether you are creating a new analysis or running an existing one.
Operating Point Generate the operating point for the analysis by using a simulation script.
Simulation Script Name Select a simulation script that configures the model and test rig for the vibration analysis.
Input Channels Specify which input (and actuators) and output channels should be active during the analysis. Note that if you select N input channels and M output channels, then N*M transfer functions will be generated.
The remainder of the options available in this dialog box are described in the help for the Adams/Vibration Perform Vibration Analysis dialog box.
57Dialog Box - F1 HelpRoad-Profile Generation
Road-Profile GenerationRide -> Tools -> Road-Profile Generation
Generates a road profile using the Sayers (see References) model. Learn about Road-Profile Generation Tool.
For the option: Do the following:
See Parameter Variables for Sayers Roughness Model.
Elevation PSD Parameter: Ge Enter a value for the Ge parameter.
Velocity PSD Parameter: Gs Enter a value for the Gs parameter.
Acceleration PSD Parameter: Ga Enter a value for the Ga parameter.
Profile Length Enter the length of the road whose profile you want the model to approximate.
Sample Interval Enter the distance between profile data points. Sample interval is the same as the absolute value of the difference in the Station of two adjacent data points.
Correlation Baselength Enter the quantity LB (used in Equation (3)).
Output Filename For RPC III File
Enter the full path to a file that Adams/Car Ride will create to store the profile data. Adams/Car Ride stores the data in the RPC III file format (Learn about RPC III Format). This is a binary file format developed by MTS [4]. The file will contain two channels: channels 1 and 2, which will contain the profile data for the left and right wheeltracks, respectively. The independent variable of the file is station, measured in meters (m). The two dependent variables (channels 1 and 2) are road elevation, measured in millimeters (mm).
Tips on Entering File Names in Text Boxes.
After you create the RPC file, you can view it in Adams/PostProcessor. To do so, go to Adams/PostProcessor (F8), select File -> Import -> RPC File, and then select the file you created. Plot the two channels: LElev and RElev. Note that the y-axis will be labeled mm, but the x-axis will be labeled No Units. The actual units are meters (m), but, currently the RPC III file format doesn't provide a way to store this information, so there is nothing in the file that Adams/PostProcessor could use to create the units label for the x-axis.
The following channel names appear in Adams/PostProcessor, when you import the file and plot it. Normally, however, you access the RPC III files by referring to channel numbers rather than channel names.
Adams/Car RideRoad-Profile Generation
58
Channel Name for Left Wheeltrack
Enter a name for channel 1.
Channel Name for Right Wheeltrack
Enter a name for channel 2.
Seed For Random Numbers Enter an integer that determines how the random-number generator (used for creating a Gaussian distribution for the Sayers model) is seeded.
• If the seed is negative, for example, -1, Adams/Car Ride uses the computer's clock as a seed. Therefore, multiple RPC III files created for the same set of profile parameters will be different. An infinite number of profiles can be generated to match the same set of Sayers-model parameters.
• If the seed is greater than zero, Adams/Car Ride uses the value of the seed as the seed to the random-number generator. Therefore, each RPC III file created for the same set of parameters, and the same seed, will be identical. This, then, is a means of generating reproducible profiles with the Sayers model.
For the option: Do the following:
59Dialog Box - F1 HelpRoad-Profile Setup: ARIDE_FOUR_POST_TESTRIG
Road-Profile Setup: ARIDE_FOUR_POST_TESTRIGRide -> Full-Vehicle Analysis -> Four-Post Test Rig -> Set Up Road Profiles
Sets up the road profile (See Road-Profile Generation Tool).
For the option: Do the following:
Profile Source Select one of the following:
• RPC files - Allows you to use road-profile data stored in the RPC III file format to drive the four-post test-rig actuators in displacement. Such data could be measured (for example, from a profilometer) or generated from a mathematical model for road roughness. In particular, Ride -> Tools -> Road-Profile Generation displays a dialog box for such a mathematical model. The data generated is stored in the RPC III format. Therefore, you can use that tool to generate data to select from the current dialog box. Learn about RPC III Format.
• sum RPC files & table functions - Takes the height road-profile data from both sources and sums it together as the input to the actuators. Therefore, is useful if you want to superimpose a bump on top of a road profile. For example, you might represent the overall road with data from RPC files, but then create a bump with a table function.
• table functions - Allows you to drive the actuators in displacement using a table function whose data is stored in a TeimOrbit file (see TeimOrbit File Format). You can create and edit such tables with the Curve Manager. (For Beta, we recommend that you use the example table-function data file as templates to create your own data by directly editing the files, instead of the Curve Manager.)
See Curve Manager.
Vehicle Speed Select the forward speed of travel for the vehicle. Note that negative values are not allowed.
The vehicle does not travel down a road with the four-post test rig: the wheels do not spin and the mass-center velocity hovers around zero. However, the vertical-height inputs to the rear wheels lag behind those of the front wheels by (Calculated Time Lag) = (Calculated Wheelbase)/(Vehicle Speed). Therefore, the test rig cam approximates a road very well.
Calculated Wheelbase Displays the calculated wheelbase. The wheelbase is derived from the locations of the spindle-centers in the vehicle assembly. It is the average of the for-aft distance for the left and right side of the vehicle, evaluated in the design configuration (not in the static-equilibrium configuration).
Adams/Car RideRoad-Profile Setup: ARIDE_FOUR_POST_TESTRIG
60
Calculated Time Lag Displays the time that inputs to the rear wheels lag behind those of the front. It is calculated as explained for Vehicle Speed.
If you set Profile Source to RPC files, Adams/Car Ride displays the following options:
RPC Files With Road Profiles - Left Wheeltrack Profile/Right Wheeltrack Profile
File Name Select the full path to an RPC III file with road-profile data. If you right-click and Search the <aride_shared> database, you will see at least two RPC III files in the "road_profiles.tbl" directory: "example.rsp" and "flat.rsp". Note that .rsp is the extension that denotes RPC files.
Use flat.rsp if you want zero vertical input to one (or both) sides of the vehicle. Both the left and right wheeltracks can refer to the same RPC file, but they can also refer to different files.
Channel Number Enter the number of the channel that has the data you want to use. Data is stored in RPC III files by channel. Each channel is referenced by its number. Both the left and right wheeltracks can use the same channel from the same file, different channels from the same file, or the same channel or different channels (numbers) from different files.
You can give the vehicle symmetric inputs if you use the same channel number from the same file for both wheeltracks. Note that the Adams/Car Ride Road-Profile Generation tool always uses channel 1 for the left wheeltrack and channel 2 for the right wheeltrack.
If you set Profile Source to sum RPC files & table functions or to table functions, Adams/Car Ride displays the following options:
Table-Function Property Files With Road Profiles - Left Wheeltrack Profile/Right Wheeltrack Profile
File Name Select the full path to a TeimOrbit text file with road-profile data. If you right-click and Search the <aride_shared> database, you will see at least two RPC III files in the "road_profiles.tbl" directory: "bump_1inch.rpt" and "flat.rpt". Note that .rpt is the extension that denotes TeimOrbit road-profile data files.).
Use flat.rpt if you want zero vertical input to one (or both) sides of the vehicle. Both the left and right wheeltracks can refer to the same TeimOrbit file, but they can also refer to different files. You can give the vehicle symmetric inputs if you use the same file for both wheeltracks.
Select to display the Data Editor/Viewer to plot the wheeltrack profile.
For the option: Do the following:
1Appendix
Appendix
Adams/Car RideConvergence Tolerance
2
Convergence ToleranceConvergence tolerance is the tolerance that determines when the objective function has converged. The optimization stops when this tolerance is met. Specifically, the convergence tolerance is satisfied if:
(convergence tolerance) > (error_dynamic_stiffness + error_loss_angle)*100/number_of_frequencies
where
error_dynamic_stiffness = Sqrt(Sum_of_all((stiffness_calculated - stiffness_measured)**2))/stiffness_measured_middle
and
error_loss_angle = Sqrt(Sum_of_all((loss_angle_calculated - loss_angle_measured)**2))/loss_angle_middle_measured)
3AppendixDamper Sweep
Damper Sweep
Adams/Car RideExample Input Hydromount Property File
4
Example Input Hydromount Property FileThe following is a sample input hydromount property file (extension .hbu). This sample file contains the minimum set of required data.
Learn About Input Hydromount Property Files.
$-----------------------------------------------------------MDI_HEADER[MDI_HEADER] FILE_TYPE = 'hbu' FILE_VERSION = 1.0 FILE_FORMAT = 'ASCII'$----------------------------------------------------------------UNITS [UNITS] LENGTH = 'mm' FORCE = 'newton' ANGLE = 'degrees' MASS = 'kg' TIME = 'second' $--------------------------------------------------------------GENERAL [GENERAL] DEFINITION = '.ride.attachment.ac_hydro_bushing' HYDRO_COORDINATE = 'z' BUSHING_PROPERTY_FILE = '<ride>/bushings.tbl/mdi_0001.bus' SUPER_IMPOSE_BUSHING = 'off' $----------------------------HYDRO_TEST_DATA [HYDRO_TEST_DATA]
{amplitude frequency cdyn phase}
0.100000 5.000000 620.0 7.7
0.100000 8.000000 652.0 16.2
0.100000 10.000000 776.0 20.4
0.100000 12.000000 911.0 20.2
0.100000 15.000000 1038.0 12.9
0.100000 20.000000 963.0 5.5
0.100000 25.000000 902.0 4.0
0.100000 30.000000 881.0 4.3
0.100000 40.000000 841.0 5.3
0.100000 50.000000v 838.0 6.6
0.800000 5.000000 620.0 9.9
0.800000 8.000000 620.0 20.9
0.800000 10.000000 691.0 29.1
0.800000 12.000000 855.0 32.4
5AppendixExample Input Hydromount Property File
0.800000 15.000000 1085.0 25.2
0.800000 20.000000 1142.0 12.0
0.800000 25.000000 1100.0 7.0
0.800000 30.000000 1068.0 5.4
0.800000 40.000000 1020.0 5.3
0.800000 50.000000 1031.0 5.6
Adams/Car RideForce vs Displacement for Linear Damper
6
Force vs Displacement for Linear Damper
7AppendixFourier Method
Fourier Method a0 = Integral(2*sweep_frequency*fx) a1 = Integral(2*sweep_frequency*cos(2*pi*sweep_frequency*time)*fx) b1 = Integral(2*sweep_frequency*sin(2*pi*sweep_frequency*time)*fx) loss_angle = atan(a1/b1) f_ampl = a1 /sin(loss_angle) f_min = a0/2 - f_ampl f_max = a0/2 + f_ampl loss_energy = a1 * f_ampl * PI
Adams/Car RideIntegrator Error
8
Integrator Error Integrator error is the allowed error of the state variables of the hydromount during numerical integration. The state variables are the displacement (mm) and velocity (mm/s) of the effective fluid mass. The same numerical value, specified in the Integrator Error text box, is used for both states.
The numerical integration is done with a 4th-order Runge-Kutta method. The time-step size is automatically varied during the integration in accord with the value of the error tolerance. The error is calculated based on two means of computing the next values of the state variables: one explicit and the other implicit. If the results of the explicit and implicit computations differ by more than the error tolerance for either state variable, then the time-step size is decreased and the integrator tries again. If the error is very small compared to the error tolerance for both state variables, then the time-step size is increased for the next time interval.
9AppendixMax Optimizer Loops
Max Optimizer Loops Max optimizer loops is the maximum number of iterations the optimizer is allowed to perform to satisfy the convergence tolerance. The optimizer will stop after this number of iterations have been performed even if the convergence tolerance is not satisfied.
One iteration constitutes the calculation of a pair of dynamic stiffness and loss angle values for each amplitude and frequency of the measured data. The progress bar shows the percentage of the pairs of calculated values that have so far been obtained for a single iteration.
Adams/Car RideMin-Max Method
10
Min-Max Method
Fmin and Fmax are measured at velocity = 0.
Dynamic stiffness CDYN = (Fmax - Fmin)/(2*amplitude)
Strain energy W = (Fmax - Fmin)*amplitude/4
Loss energy dW = abs(Integral(F(t)*vel(t) dt)) in the interval [(i-1)*2pi , i*2pi]
Relative damping PSI = dW / W
Loss angle PHI = asin( PSI / (2*pi) )
11AppendixPhase
Phase
Adams/Car RidePhase 2
12
Phase 2
13AppendixResults with 1 mm amplitude and 5 Hz
Results with 1 mm amplitude and 5 Hz
Adams/Car RideSawtooth
14
Sawtooth
15AppendixStation
StationStation is the projection of the absolute arc-length in 3D space of the road centerline, from some reference point to a point of interest, projected into the global x-y plane.
Adams/Car RideSteady-State Error
16
Steady-State Error Steady-state error is the allowed difference for the dynamic stiffness and loss angle between two consecutive cycles of the sinusoidal excitation. The computations for a particular frequency of excitation terminate when the calculated error is less than the tolerance.
The steady-state error tolerance is dimensionless. Specifically, the error tolerance is satisfied if, for two consecutive cycles of the sinusoidal excitation:
error_dynamic_stiffness < (steady-state error)
and
error_loss_angle < (steady-state error)
where,
error_dynamic_stiffness =Max(stiffness_calculated(amplitude_1)/stiffness_max_measured(amplitude_1),...,stiffness_calculated(amplitude_n)/stiffness_max_measured(amplitude_n))
error_loss_angle =Max(loss_angle_calculated(amplitude_1)/loss_angle_max_measured(amplitude_1),...,loss_angle_calculated(amplitude_n)/loss_angle_max_measured(amplitude_n))
and the stiffness and cdyn and loss angle are calculated over one sinusoid cycle.
The steady state error indicates when the system is considered to be in steady state condition. This is used to shorten the overall CPU time.
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