Italy Wheel Rail Dynamic of DMU IC4 Car - Simpack.com

Wheel Rail Dynamic of DMU IC4 Car for DSB: 

Modelling of the effect of Secondary Air Spring 

on Calculation Results and Advanced Analysis 

for Controlling Car Body Angle. 

AnsaldoBreda 

D. Vannucci, G. Saporito, M. Romani 

Politecnico di Milano 

A. Facchinetti, Collina A. 

21st and 22nd March 2006 SIMPACK User Meeting 2006

Summary 

Introduction 

AB engineering and MBS 

IC4 Vehicle description 

The secondary suspension 

– Secondary suspension study for IC4 

– Different levels of modelling the suspension 

– remarks 

Developing of a test bench air spring characterizing 

– Description 

– Test of air spring 

– Static characterizing 

– Dynamic characterizing 

Developing of the numerical model - Simpack co-simulation 

– Simple lumped parameter 

– Finite element model 

Conclusion 


AB Engineering and MBS 

In 1998 AB introduced MBS in 

the engineering process 

Typical application: wheel rail 

vehicle 

MBS Target: 

– Testing the vehicle behaviour 

according to UIC518 

complete models are involved 

– Components design support 

Usually detailed sub models are 

involved 


AB Engineering and MBS 

Extension of MBS simulation to the 

Dynamic Analysis works transversally on all projects 

Tram 

high and low floor and partially low, Sirio, Los Angeles 

Railway vehicles 

EMU, DMU, Locomotive, High speed train 

Mass transit 

Madrid, Copenhagen, Brescia 


IC4 Vehicle: description 

Project developed in Simpack 

– Eight three (83) Diesel Multiple Units Trains 

– Each train consists of three articulated 

coaches 

– Coaches 86m long and 208 seats capability 



Vehicle description 

Total seats number 

Max speed 

Main characteristics 

Base train set configuration 

4 cars with 3 articulations 

M1c+T2hk+T3+M4c M1c : Motor car with cab 

T2hk : Intermediate trailer car 

with handicap facilities 

T3: Intermediate trailer car 

M4c : Motor car with cab 

208 seats arranged (faced 

seats configuration) Higher 

seats available in other 

configuration 

200 km/h 



Substructures involved fully parametric for the bogies 

The Three different bogie typology were modelled in 

substructures 

– Head motor bogie 

– Trailer Jacobs bogie 

– Motor Jacobs bogie 



Global model 

Different target analysis 

– Force analysis (UIC518) 

– Comfort analysis (Elastic bodies) 



Global model 

– Model database, makes the model suitable for different 

configurations study 

– Rigid bodies for the force analysis 

– Elastic bodies bring yield eigen mode information 

– Particular mode to take into account concentrate load 

(introduced by power unit) 


IC4 Vehicle: secondary suspension 

System air spring 

– Air bellow connected to expansion 

reservoir 

– Air moves from bellow to tank under 

vertical loading to contain the 

pressure gap 

– Vertical stiffness is proportional to the 

air volume 

– In vertical direction, the lower the 

stiffness is the lower is the natural 

frequency of the system 

Variables of the system: 

– Volume 

– Temperature 

– Mass 

– Density 

– Energy 

– Shape 



The system modified to keep levelled the car body 

Final detailed model 

– Levelling valve 

– Pneumatic system 

– Vertical position is 

controlled by 

pressure feed back, 

doesn’t change with 

load 



First design step: lateral behaviour 

Air spring modelled by extrapolating the lateral 

stiffness related to the load condition 

It comes from the supplier background at earlier step of the 

project 

At the end of design supplier will confirm data by means of 

type test 



First design step: vertical behaviour 

– Bouncing frequency as start parameter 

– Vertical stiffness is evaluated from load and frequency 

– This condition is frozen as starting 

point of the project: 

– Only one parameter is needed 

– At the end of project test type has to 

be performed by the supplier 

21st and 22nd March 2006 SIMPACK User Meeting 2006 

f 

= 

1 

2 

k 

M


Vertical behaviour: second approach, the Simpack linear spring 

In this case also a physical description of the 

reservoir is allowed: 

K 1 is the stiffness of the main volume 

K 2 is the stiffness of the reservoir 

K 3 is the stiffness due to the effective contact 

area changing 

K 4 is the stiffness of the vertical bumper 



Vertical behaviour: second approach, the Simpack linear spring 

– Bigger number of configuration parameter needed 

– Not all could be given at earlier step of the project 

– Frequency response is considered by this kind of element 



Vertical behaviour: third approach, closed loop model for modelling the 

pneumatic system 



Vertical behaviour: Advanced levelling in closed loop model for 

modelling the pneumatic system 

– High number of configuration parameters to be set 

– Levelling valve position 

– Valves characteristics 

– Information set known only at the final state of the project 



Simulation test: the three different model for modelling the secondary 

suspension 



Simulation test: the three different model for modelling the secondary 

suspension 

– Data history has been 

processed obeying 

UIC518 

– Filtering algorithm has 

been implemented in 

Matlab 

– Output are shown for 

Y\Q 

Y lateral force 

Q wheel force 


Remarks: contact forces 

First approach the “equivalent air spring” is the best approach for wheel 

rail contact force calculating 

– Few configuration parameters are required, very low calculating time, output 

results agree with the other, more complex, models 

– Good design methodology 

– Good the comparison with the running tests 


Remarks: comfort 

The “equivalent” air spring gives good efforts for its simplicity, but 

calculation output doesn’t depend on frequency of the input 

Unsuitable for comfort analysis, the second modelling approach is 

needed to simulate the load transfer into the vehicle car body 

The linear spring gives a more realistic description of vehicle comfort 

– More parameters are required 

– More CPU time is spent 

– More modelling time needed 

– Good solution for comfort analysis adopting the flexible body model 


Remarks: roll angle control 

First two approaches are merely passive: 

– No control system on coach roll angle is simulated 

– If we need to model roll angle control we have to complicate the model 

introducing the active air spring 


Test bench: 

In IC4 have been developed three different kind of models 

– Few parameter model 

– Linear spring model 

– Closed loop model 

Intending now to set up simple model requiring relatively few 

parameters 

– Accessible at project beginning 

– Allow to explore the frequency response of elements 

– Test stiffness data before supplier type test are available 


Test bench 

To improve the description of the system air spring, important 

collaboration with Politecnico di Milano has been started 

Target of collaboration: 

– build and set up a test bench 

– characterizing air spring 

Static 

Dynamic 

– reservoir and pneumatic system 

frequency response 

– Set up and validate a numerical 

model of the system 


Dynamometric 

balance 

Test bench: description 

Test setup: frontal 

Loading 

beam 

Vertical 

actuators 

Upper interface 

plate 

Lower interface 

plate Dynamometric 

balance 

Actual running condition are simulated 

on air springs 

Horizontal 

actuator 

Loading system 

– Two vertical actuators 

– One horizontal actuator 

– Load beam 

– Each spring connected to balance 





Lower 

interface plate 

Test setup: lateral 

Upper interface 

plate 

Dynamometric 

balance 

Vertical actuator 

Loading beam 

Longitudinal support 

Supports to get the system equilibrated 

Interface plates were realized for air springs 





Test setup: pneumatic system 

Rigid duct 

Air supplying 

Reservoir 

Levelling valve 

Air spring 

Rigid duct 

Complete pneumatic circuit is simulated 

Air spring pneumatic circuit: 

– Reservoir 

– Levelling valve 

Air supplying 

– Compressor 

– Check valve 


Test bench: Force and displacement measure 

Displacement: from 

laser position 

Force: balance Torque: balance 


Test bench: pressure measurement 

Pressure measurement: test of pneumatic plant behaviour 


Test bench: Static characteristics 

Identifying element stiffness matrix 

– Different preload as initial condition 


Simpack co-simulating: co simulating: start point 

Identifying element stiffness matrix 

Load [kN] Fq [Hz] K [N/m] KBumper [N/m] P [atm] AEFF [m 2 ] 

The experimental test allows to confirm supplier’s 

type test 120 0.991 474980 4545000 4.8548 0.2472 

Extend 145 the set 0.998of configuration 570000 6175000 parameters 616565 0.2352 related 

to the element 

Configure a starting point to build a low-frequency 

model using via Simat-Simulink co-simulation 

Load [kN] Fq [Hz] K [N/m] KBumper [N/m] P [atm] AEFF [m 2 ] 


Simpack co-simulating: co simulating: physics modelling 

– Perfect gas behaviour 

– Adiabatic transformation 

– Volume of the system, V=V 0 +V reservoir 

– Effective Area changing is negligible 

– Volume changing, HV = z·A Eff 

0 0 

P = P ; M = ; 

0 

RT 

0 

0 P 0 = P 0 + 

P0 

PV 

RT 

RT0 

( V A z) 

; 

Eff 

PV 

0 


0 

0 

y 

A 

z 

= 

0;

Simpack co-simulating: co simulating: Simpack model 

Vertical behaviour: natural frequency identifying 

– Vertical preload from the pressure of the starting point 

– z signal goes into Simulink 

– Force perturbation return in Simpack 




– The Effective area changing has to be considered 




– By considering the effective area changing the natural frequency agrees experimental value 

– Verify in other target load condition 

Load[kN] Fq[Hz] K[N/m] KBumper [N/m] P[atm] AEFF[m 2 ] 


A 

z 

= 

0;

Test bench: Dynamic characterization 

Vertical behaviour 

– Identifying the transferring function vertical displacement-air spring force 

– Different load condition 

– Different frequency and amplitude 



Vertical behaviour: Pressures in different location of the system 

– 0.5 Hz pressures in different location 

of the system are in phase 

concordance 

– 2.5 Hz pressures in different location of the 

system, no more phase concordance 




– 4 Hz pressures in different location of the system, in phase opposition 




– 20 Hz pressures in different location of the system, no pressure response in reservoir 




– Frequency domain response in target load condition for different amplitude 


Simpack co-simulating: co simulating: physics 

modelling 

– Two volumes (reservoir and air spring) connecting duct 

– Input of the system is the x position of the air spring plate 

– Lumped parameters for air spring and reservoir 

Air spring 

duct 

Reservoir 



modelling 



– Lumped parameters for air spring and reservoir 

Air spring 

duct 

Reservoir 



modelling 



– finite element description for air motion in the duct 

Air spring 

duct 

Reservoir 



modelling 

Air spring 

– Adiabatic condition 

– Boundary condition given by lumped systems 

duct 

Reservoir 



modelling 

Preliminary model results comparison 

A 

Ph 


Conclusions 

Different approaches to secondary suspension design 

during developing of IC4 project 

First “equivalent spring” in the earlier step 

– Very low parameter number 

– Good for contact force evaluation 

Linear spring or advanced spring model in advanced 

steps 

– Increase of the parameter request 

– x Comfort analysis 

Closed loop model 

– For detailed setting in the final step of the project 

– Control system of the pneumatic plant setting 

– General verify on the vehicle 


Conclusions 

Study for setting a new model depending mainly on the 

geometry and on a few set of parameters for predict the 

frequency response in earlier step of the project 

Research activity: 

– Characterizing static and dynamic behaviour of elements 

– Enlarge data available related to air spring 

– Compare supplier type test data 

– Testing a numerical model co-simulating Simpack/Simulink 

More x validation test are necessary to test and set up 

completely the numerical model presented 

Co-simulation offer an actual chance to model and set up 

car control system

Italy Wheel Rail Dynamic of DMU IC4 Car - Simpack.com

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