Simulation

I. Introduction ...................................................................................................................... 360

II. Modelling Vehicle-Track Interaction............................................................................. 361

A. Vehicle Models ........................................................................................................ 361

B. Vehicle Models — Body Components.................................................................... 363

C. Vehicle Models — Suspension Components .......................................................... 366

D. Track Models ........................................................................................................... 369

E. Wheel-Rail Contact Models ................................................................................... 370

III. Simulation Methods ......................................................................................................... 371

A. Multibody Systems and Equations of Motion......................................................... 371

B. Solution Methods ..................................................................................................... 371

C. Eigenvalue Analysis................................................................................................. 372

D. Stochastic Analysis .................................................................................................. 372

E. Time-Stepping Integration ....................................................................................... 372

F. Quasistatic Solution Method.................................................................................... 373

IV. Computer Simulation ....................................................................................................... 373

A. Historical Development ........................................................................................... 373

B. Multibody Simulation Tools .................................................................................... 376

C. Flexible Bodies ........................................................................................................ 378

D. Benchmarking .......................................................................................................... 378

V. Dynamics in Railway Vehicle Engineering .................................................................... 379

A. Introduction .............................................................................................................. 379

B. Railway Vehicle Engineering Processes ................................................................. 380

C. Tasks and Methods in Dynamic Analysis ............................................................... 381

D. Eigenbehaviour......................................................................................................... 382

1. Eigenvalue Analysis .......................................................................................... 382

2. Simulation of Eigenbehaviour .......................................................................... 384

E. Stability Analysis ..................................................................................................... 385

1. Introduction ....................................................................................................... 385

2. Linearised Stability Analysis ............................................................................ 385

3. Nonlinear Stability Analysis ............................................................................. 390

F. Run on Track with Irregularities ............................................................................. 395

1. Definition of Running Behaviour, Ride Characteristics and Comfort ............. 395

2. Ride Characteristics........................................................................................... 396

3. Ride Comfort ..................................................................................................... 398

G. Curving..................................................................................................................... 401

1. Assessment of Curving Properties .................................................................... 401

2. Running Safety .................................................................................................. 403

3. Track Loading and Wear .................................................................................. 404

4. Curving Optimisation Using Self-Steering and Interconnected Wheelsets ..... 406

H. Running Dynamics under the Influence of External Loads.................................... 409

1. Influence of Crosswind...................................................................................... 409

2. Influence of Coupler Forces.............................................................................. 410

3. Interaction between Vehicle and Traction Dynamics ...................................... 412

VI. Conclusions ...................................................................................................................... 415

Acknowledgments ........................................................................................................................ 416

Nomenclature................................................................................................................................ 416

References..................................................................................................................................... 417

With the advent of powerful computers simulation of complex mechanical systems has become a

real possibility. A computer model of a railway vehicle can be constructed and run on typical or

measured track in a virtual environment, and a wide range of possible designs or parameter changes

can be investigated. Outputs from the model can be set up to provide accurate predictions of the

dynamic behaviour of the vehicle and its interaction with the track. Optimisation of suspension or

other parts of the system can be carried out, and levels of forces and accelerations can be checked

against standards to ensure safe operation.