pneumatic suspension 3 spp
TRANSCRIPT
1
GraSMech – Multibody 1
Computer-aided analysis of multibody dynamics (part 2)
Multiphysics modelling of railway vehicle equipped with pneumatic suspension
Nicolas Docquier([email protected])
GraSMech – Multibody 2
Contents
Railway vehicle descriptionClassical railway vehicleSecondary pneumatic suspension
Modelling and numerical methodsMultibodyPneumaticCo-simulation
ApplicationDelta Q/QCurve entry
GraSMech – Multibody 3
Contents
Railway vehicle descriptionClassical railway vehicleSecondary pneumatic suspension
Modelling and numerical methodsMultibodyPneumaticCo-simulation
ApplicationDelta Q/QCurve entry
2
GraSMech – Multibody 4
Railway vehicles
Principle partsCarbody
Running gearRigid-frame vehicles
Bogie vehicles
GraSMech – Multibody 5
Conventional bogie
Main components
Bolster
Bogie frame
Wheelset Axle box
Primarysuspension
Secondary suspension
GraSMech – Multibody 6
Conventional bogie
Main components
Anti-roll bar
Bolster
Bogie frame
Wheelset Axle box
Primarysuspension
Secondary suspension
3
GraSMech – Multibody 7
Conventional bogie
Main components
Traction rod
Anti-roll bar
Bolster
Bogie frame
Wheelset Axle box
Primarysuspension
Secondary suspension
GraSMech – Multibody 8
Variant of the conventional bogie
Conventional bogie – Jakob’s bogie
Tyred bogieIndependant wheels bogie
GraSMech – Multibody 9
Pneumatic circuit
Pneumatic bellow
Stiffness:
Effective area: Ae = 0.1 … 0.4 m2
Volume: V0 = 10 … 40 l
Static load: 50 … 130 kNpressure: p0 = 4 … 8 bar
20
0
eA pkV
≈
4
GraSMech – Multibody 10
Pneumatic circuit
Auxiliary tank
VR = 20…100 l
volume stiffness2
0
0
e
r
A pkV V
≈+
GraSMech – Multibody 11
Pneumatic circuit
Pipe orifice
pressure drop pneumatic damping
GraSMech – Multibody 12
Pneumatic circuit
Levelling valve
5
GraSMech – Multibody 13
Pneumatic circuit
Levelling valve
load carbody heightair admission
GraSMech – Multibody 14
Pneumatic circuit
Levelling valve
load carbody heightair exhaust
GraSMech – Multibody 15
Pneumatic circuit
Levelling valve
neutral position
admission
Air flow
Lever position
pb1
pb2<pb1
exhaust
6
GraSMech – Multibody 16
Pneumatic circuit
Safety valve
carbody heightsudden air exhaust
Air flow
Lever position
GraSMech – Multibody 17
Pneumatic circuit
Differential pressure valve
Air flow
(pr-pl)
GraSMech – Multibody 18
Pneumatic circuit configurations
4 point suspension
2 point suspension
7
GraSMech – Multibody 19
Suspension classification
Bogie
Levelling
Anti-roll bar
Auxiliary tank
Conventional Jakob’s bogie
2 points 4 points
With Without
With Without
GraSMech – Multibody 20
Contents
Railway vehicle descriptionClassical railway vehicleSecondary pneumatic suspension
Modelling and numerical methodsMultibodyPneumaticCo-simulation
ApplicationDelta Q/QCurve entry
GraSMech – Multibody 21
Multibody modelling
Carbody modelling6 dofTorsion
2 rigid bodies1 revolute spring
Bogie modelling4 bodies
BolsterFrame2 wheelset
Wheel/rail contact constraint
8
GraSMech – Multibody 22
Multibody modelling
SimpackRelative coordinate as RobotranJoint library
GraSMech – Multibody 23
Multibody modelling
SimpackRelative coordinate as RobotranJoint library
GraSMech – Multibody 24
Multibody modelling
SimpackDedicated railway interface
9
GraSMech – Multibody 25
Multibody modelling
SimpackDedicated railway interface
GraSMech – Multibody 26
Pneumatic modelling
Pneumatic circuit
GraSMech – Multibody 27
Valve modelling
Flow
(pd-pg)
admission
Flow
Lever position
pb1
pb2<pb1
exhaust
Differential valve Levelling valve Exhaust valve
q = f (pbellow, lever pos) q = f (pbellow, lever pos)
q = f (pd, pg)
Flow
Lever position
10
GraSMech – Multibody 28
Bellow-tank subsystem
Simpack approachEquation of motion of the pipe
Volume variation in the bellow and tank
Air flow approachBellow
Tank
Pipe
( )c tb c cc
p Rq T p VVγ
= − &&
r tbr
p Rq TVγ
= −&
Vp csteM
γ⎛ ⎞ =⎜ ⎟⎝ ⎠
Mass Volume
( ) 02 rc
2 =−++ ttt
t AppyAym &&& ξρ
( ),rc r c rcq f p p q= −& ( )rc r cq f p p= −differential equation algebraic equation
GraSMech – Multibody 29
Bellow-tank subsystem
Model comparisonSinusoidal excitation
z(t) = zmax sin (2π f t)
Reaction force F = (pc-pa)Ae
-5 0 5
x 10-3
3.6
3.8
4
4.2
4.4
4.6x 10
4
z [m]
F [N
]
0 0.2 0.4 0.6 0.8 13.6
3.8
4
4.2
4.4
4.6x 10
4
Time [s]
Forc
e [N
]
GraSMech – Multibody 30
Bellow-tank subsystem
Frequencial analysisDynamic stiffness Damping
Simpack
Différential
Algebraic
0 5 10 15 20 25 302
4
6
8
10
12x 105
Frequency [Hz]
Stif
fnes
s[N
/m]
0 5 10 15 20 25 300
0.5
1
1.5
2
2.5
3
Frequency [Hz]
Dam
ping
[-]
11
GraSMech – Multibody 31
Numerical method
Multibody
PneumaticSimulink
Simpack
Hybrid system
GraSMech – Multibody 32
Numerical method
Co-Simulation2 process integrated in parallel
Interaction at fixed time step
Simpack( )
Matlab-Simulink( )
MultibodyModel
PneumaticModel
z, z, L&F
GraSMech – Multibody 33
Contents
Railway vehicle descriptionClassical railway vehicleSecondary pneumatic suspension
Modelling and numerical methodsMultibodyPneumaticCo-simulation
ApplicationDelta Q/QCurve entry
12
GraSMech – Multibody 34
Main characteristics
No anti-roll bar
4 point suspension
Auxiliary tank in the bolster
No pipe between the bellow and the tankalgebraic model for the orifice
Pressure source connected to the auxiliary tank
Actual vehicle analysis
GraSMech – Multibody 35
Description of the testStationary vehicleWedges placed under some wheels
Experimental observationsCarbody oscillations
Overloaded bellows:Air admission through levelling valves
Unloaded bellows : Air exhaust through levelling valvesAir exhaust through safety valves
Differential valves engaged
Essai DeltaQ/Q
Bad comfort
62 mm
GraSMech – Multibody 36
DeltaQ/Q test
Reference configuration
No equilibrium
Exhaust valve engagedbeginning of oscillations
Air admission on one side,air exhaust on the other side
0 10 20 30 40
-20
0
20
40
Time [s]
Dis
plac
emen
t [m
m]
Rear left
0 10 20 30 40
-20
0
20
40
Time [s]
Rear right
0 10 20 30 40
-20
0
20
40Front right
0 10 20 30 40
-20
0
20
40
Dis
plac
emen
t [m
m]
Front left
13
GraSMech – Multibody 37
0 20 40 60
-20
0
20
40Rear right
Time [s]0 20 40 60
-20
0
20
40Rear left
Time [s]
Dis
plac
emen
t [m
m]
0 20 40 60
-20
0
20
40Front right
0 20 40 60
-20
0
20
40Front left
Dép
lace
men
t [m
m]
DeltaQ/Q test
Smaller pipe orificeLarge oscillations avoided
Safety valve engaged after 50s no equilibrium
0 10 20 30 40 50 60 70-30
-20
-10
0
10
20
30
40Rear right
Time [s]
Disp
lace
men
t [m
m]
GraSMech – Multibody 38
|pga-pdr| < 2.25 bar
DeltaQ/Q test
Differential valve modificationpga-pdr > 2.25 bar
pga pdr pga pdr
pa
0 20 40 60 80 100-30
-20
-10
0
10
20
30
40
Time [s]
Disp
lace
men
t [m
m]
Rear right
airflow between auxilary tanks air exhaust to atmosphere
GraSMech – Multibody 39
0 20 40 60 80-2
-1.5
-1
-0.5
0
Time [s]
Rol
l ang
le [°
]
Curve entry
Full loadEmpty carbody
Curve radius 100 mInitial speed 10 m/s
lateral accelertation 1 m/s²
0 20 40 60 80-2
-1.5
-1
-0.5
0
Time [s]
Rol
l ang
le [°
]
All valves connectedSafety valve disconnectedLevelling valve and safety valve disconnected
14
GraSMech – Multibody 40
Conclusion
Pneumatic modellingModel of the bellow-tankModel of the complete circuit (valves…)
Study of an actual vehicle systemAnalysis of an experimental problemSolution proposal investigation
Future work1D model of the pipe Better description of the valvesComparison of the various pneumatic circuit configurations