82215765 autodyn basics
DESCRIPTION
autodyn basicTRANSCRIPT
-
5/21/2018 82215765 Autodyn Basics
1/32
3-1ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Chapter 3
AUTODYN Basics
ANSYS AUTODYN
-
5/21/2018 82215765 Autodyn Basics
2/32
AUTODYN Basics
3-2ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training ManualStructured and Unstructured Parts (Meshes)
An AUTODYN Part can use aStructured mesh or an Unstructuredmesh
Structured meshes can be generated inAUTODYN
Use (I,J,K) index space
Unstructured meshes must be imported(e.g. from Workbench)
Lagrange Parts (Solid, Shell, Beam)
Can be Structured or Unstructured Unstructured Parts are solved more
efficiently (speed and memory)
A Structured Part can be converted to anUnstructured Part prior to solving
Lagrange Parts (structured or
unstructured) can be used to fill regionsof Euler and SPH Parts
Euler and ALE Parts
Always Structured
Euler meshes are usually rectilinear
-
5/21/2018 82215765 Autodyn Basics
3/32
AUTODYN Basics
3-3ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
i
j i = 1 i = 11
j = 1
j = 6
Structured Parts - Index Space
Each Structured Part in AUTODYN has a defined index space (i,j) in 2D or(i,j,k) in 3D, where i, j and k are integer values ranging from 1 to Ni, Nj, Nk This index space is always rectangular
-
5/21/2018 82215765 Autodyn Basics
4/32
AUTODYN Basics
3-4ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
x
y
i = 1 i = 11
j = 1
j = 6
Structured Parts - Physical Space
Each Structured Part is also defined in a physical xyz-space, where x,y and z are real values
The mesh can have a general shape in physical space
-
5/21/2018 82215765 Autodyn Basics
5/32
AUTODYN Basics
3-5ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Index Space Physical Space
Unused
Elements
Not all elements defined in the index space need to be defined inphysical space
Elements not assigned a material are Unused
Allows complicated geometries to be meshed
Structured Parts Unused Elements
-
5/21/2018 82215765 Autodyn Basics
6/32
AUTODYN Basics
3-6ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Part Wizard allows automatic generation of qualitystructured Parts for predefined (Predef) geometries
2D Volume Box, Quad, Circle, Ogive, Rhombus, Triangle, Wedge
3D Volume Box, Hex, Cylinder, Sphere, Ogive, Fragments/Bricks
Shells Plate, Cylinder
Manually build quality structured meshes Nodes
Lines
Surfaces
Volumes
Import Structured Meshes
ICEM-CFD
TrueGrid
Part
Wizard
Creating Structured Parts
-
5/21/2018 82215765 Autodyn Basics
7/32
AUTODYN Basics
3-7ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training ManualPart Wizard
Geometry Zoning Fill
Part Wizard generates a Part in three steps
Define a Predef geometry
Define the zoning
Fill the whole Part
-
5/21/2018 82215765 Autodyn Basics
8/32
AUTODYN Basics
3-8ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training ManualPart Wizard 2D Box Predef
-
5/21/2018 82215765 Autodyn Basics
9/32
AUTODYN Basics
3-9ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training ManualPart Wizard 2D Circle Predef
-
5/21/2018 82215765 Autodyn Basics
10/32
AUTODYN Basics
3-10ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Ogive
Quads
Part Wizard 2D Predefs
Wedge
Rhombus
-
5/21/2018 82215765 Autodyn Basics
11/32
AUTODYN Basics
3-11ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training ManualPart Wizard 3D Box Predef
-
5/21/2018 82215765 Autodyn Basics
12/32
AUTODYN Basics
3-12ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training ManualPart Wizard 3D Cylinder Predef
-
5/21/2018 82215765 Autodyn Basics
13/32
AUTODYN Basics
3-13ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Sphere
Bricks / FragmentsHex
Ogive
Part Wizard 3D Predefs
-
5/21/2018 82215765 Autodyn Basics
14/32
AUTODYN Basics
3-14ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Plane
Cylinder
Part Wizard 3D Shell Predefs
-
5/21/2018 82215765 Autodyn Basics
15/32
AUTODYN Basics
3-15ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Step-by-step generation of meshesusing
Node
Line
Surface
Volume
Interpolation Extrusion
Manual Zoning
-
5/21/2018 82215765 Autodyn Basics
16/32
AUTODYN Basics
3-16ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
ANSYS, ICEM-CFD
Powerful 3D hex mesh
generator
Direct links to CAD
CATIA, Pro/Engineer, SDRC I-
DEAS, SolidWorks, Unigraphics, .
An interface to ICEM-CFD isprovided to allow import of
structured (mapped) meshes
into AUTODYN
ICEM multiblock meshes (.geo file)
Same import procedure as for
TrueGrid
Importing 3D Structured Parts
-
5/21/2018 82215765 Autodyn Basics
17/32
AUTODYN Basics
3-17ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Materials and Initial Conditions are defined fromthe Materials and Init. Cond. Dialog Panelsrespectively
Once defined, they can be applied to Parts usingthe Part Wizard and / or the Fill options in theParts dialog panel.
Define
Apply
Apply (Part Wizard)
Materials and Init ial Conditions
-
5/21/2018 82215765 Autodyn Basics
18/32
AUTODYN Basics
3-18ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training ManualFill ing Parts with Materials and Initial Conditions
Additional Block Fills
The Wizard fills each Part with one material
Additional fills can be performed after the Wizard
completes
Each fill replaces materials / initial conditions of previous fills
Lagrange elements are filled if their center lies inside
the fill region (no multi-material cells are permitted)
Additional Geometry Fill
Wizard Fill
-
5/21/2018 82215765 Autodyn Basics
19/32
AUTODYN Basics
3-19ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Boundary Conditions are defined from the Boundaries Dialog Panel
Once defined, Boundary Conditions can be applied to structured Partsusing index space from the Boundary option in the Parts dialog panel
Boundary Conditions
Define
Apply
-
5/21/2018 82215765 Autodyn Basics
20/32
AUTODYN Basics
3-20ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Boundary Conditions can be applied the outside faces of a mesh andthe outside faces of Unused regions of the mesh
The default boundary condition is:
Lagrange: Free boundary (pressure = 0.0)
Euler : Rigid wall (no flow, velocity = 0.0)
Unused elements
Filled elements
Boundary Conditions
can be applied here
Boundary Conditions
-
5/21/2018 82215765 Autodyn Basics
21/32
AUTODYN Basics
3-21ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Constant
t
Trapezoid
t
Triangular
t
ExponentPk = Pe
-kt
t
Usersubroutine
EXSTR
t
Applied to Lagrange Parts
Piecewise
t
Boundary Conditions: Stress
-
5/21/2018 82215765 Autodyn Basics
22/32
AUTODYN Basics
3-22ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Applied to Lagrange, ALE, Shell, Beam andSPH Parts
X, Y, Z Velocity Constraints
Constant Fixed at a constant value
Limit Limit position between max and min coordinates
Displacement constraint in Explicit Dynamics
Piecewise Piecewise linear segments
General Velocity Constraints
Fixed constant velocities in X, Y, Z (3D) and
fixed rotational velocities about coordinate axes
User subroutine EXVEL
User Time-Dependant X, Y, Z velocity
Boundary Conditions: Velocity
-
5/21/2018 82215765 Autodyn Basics
23/32
AUTODYN Basics
3-23ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Applied to Beam Parts
Nodal force boundary conditions
Constant, Piecewise, User
Subroutine EXFOR
x, y, z and general directions
Element force/unit lengthboundary conditions
Constant, Piecewise, User
Subroutine EXFOR
x, y, z and general directions
Boundary Conditions: Force
-
5/21/2018 82215765 Autodyn Basics
24/32
AUTODYN Basics
3-24ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Applied to Lagrange, ALE and Euler Parts
Transmits waves through cell faces
Only the perpendicular component istransmitted
The impedance of the boundary can be
specified
If impedance is set to zero the
impedance of the adjacent cell is used
The Transmit boundary condition is only
approximate and should be placed asfar as possible from regions of interest
For air blast in Euler, Outflow boundary
with p = 0.0 is recommended
cI =
Boundary Conditions: Transmit
-
5/21/2018 82215765 Autodyn Basics
25/32
AUTODYN Basics
3-25ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Applied to Euler Parts
Inflow
Specify the full state of the material flowinginto the grid (density, internal energy andvelocity)
Outflow (P = = e = 0)
Only the preferred material needs to be set
Reverse flow can be specified. If conditionsof reverse flow are reached, an externalreservoir with prescribed conditions controlsinflow
You must specify the full state of the materialflowing into the grid (density, internal energy
and velocity)
The Outflow boundary condition is onlyapproximate and should be placed as far aspossible from regions of interest
Boundary Conditions: Flow
-
5/21/2018 82215765 Autodyn Basics
26/32
AUTODYN Basics
3-26ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training ManualLagrange Interactions
Options are the same as those used in Explicit
Dynamics (ANSYS)
Details given in the Body Interactions section of the
Explicit Dynamics training course
Contact type
Trajectory (default)
Method (Formulation)
Penalty
Decomposion Response
Shell Thickness Factor
External Gap (Proximity Based)
Gap Size = Pinball Factor
Parts must be initially separated by the Gap Size
-
5/21/2018 82215765 Autodyn Basics
27/32
AUTODYN Basics
3-27ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
AUTODYN uses single precision to make optimum use of solver powerand memory, so the choice of units is important, particularly for Eulerproblems
Avoid pressures below 10-6 of a unit
Avoid cell masses less than 10-6 of a unit
The default set of units work well for virtually all problems
Length mm
Mass mg Time ms
Velocity m/s
Force mN
Stress kPa
Density g/cm3
Energy mJ
Workbench Units will be converted to the chosen AUTODYN units whenlinked
Units
-
5/21/2018 82215765 Autodyn Basics
28/32
AUTODYN Basics
3-28ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Wrapup Criteria
Must specify Cycle limit and Time limit
AUTODYN will stop and give warning if
energy error exceeds Energy fraction(default 5%)
Timestep Options
Defaults are usually OK
If Initial timestep is left zero, it is computed
as half the stability timestep
If Minimum timestep is left zero, it is
computed as 1/10th of the Initial time step
Safety factor can be safely increased to 0.9
for most Lagrange calculations
Solution Controls
-
5/21/2018 82215765 Autodyn Basics
29/32
AUTODYN Basics
3-29ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training ManualConservation Equations
Mass and Momentumare conserved exactly
Energy is notconserved exactly
Practical numericalmethods which arefully conservative haveproblems of stabilityand can be noisy
Conservation ofenergy andmomentum can bemonitored using
history plottingfeatures. Good modelset-ups and analyseswill tend to have lowerrors
Problem
Good energy
conservation
-
5/21/2018 82215765 Autodyn Basics
30/32
AUTODYN Basics
3-30ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Save Files / Results Files
Frequency specified by
Cycle increment
Time increment
Calculation can be re-started from Save files(not Results files)
Results files are significantly smaller than
Save files
Plots can be created from any Save file orResults file
Animations can be created from a sequence
of Save / Results files
More flexible than Capture image
Output Controls
-
5/21/2018 82215765 Autodyn Basics
31/32
AUTODYN Basics
3-31ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training Manual
Results Files (3D only)
Used to create plots
Allows post-processing of large models on
computers with limited resources
Files are stored in a sub folder, ident_adres
Base files ident_bcyc.ad_base
Stores model data required by Results files
Must be present to load Results file data
Results files ident_bcyc_ncyc.adres
bcyc - the cycle number for the Base file
ncyc - the cycle number for the Results file
Output Controls
-
5/21/2018 82215765 Autodyn Basics
32/32
AUTODYN Basics
3-32ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserved.February 27, 2009
Inventory #002665
Training ManualWorkshop 1: 2D Fragment Impact
Goal:
Model a multi-materialcylindrical fragmentimpacting a plate
Procedure:
Start AUTODYNstandalone
Set up the problem inusing 2D AxialSymmetry
Solve the problem
View the results
Create animations ofthe results