A new model in rail–vehicles dynamics considering nonlinear suspension components behavior

In this paper, a complete four axle rail vehicle model is addressed with 70 degrees of freedom (DOFs) including a carbody, two bogies, and four axels. In order to include the effects of the track irregularities in vehicle dynamics behavior, a simplified track model is proposed and it is validated by some experimental data and test results. As the performance of the suspension components, especially for air springs, have significant effects on rail–vehicle dynamics and ride comfort of passengers, a complete nonlinear thermo-dynamical air spring model, which is a combination of two different models, is introduced and implemented in the complete rail–vehicle dynamics. By implementing Presthus formulation [Derivation of air spring model parameters for train simulation. Master dissertation, Department of Applied Physics and Mechanical Engineering, Division of Fluid Mechanics, LULEA University, 2002], the thermo-dynamical parameters of air spring are estimated and then they are tuned based on the experimental data. The results of the complete rail–vehicle field tests, show remarkable agreement between proposed model and test data.