Effect of applied force cosimulation schemes on recoupled vehicle/track problems

Abstract

The aim of this paper is to discuss the effect of cosimulation on a railway vehicle/track/soil model. Firstly, only the vehicle and a flexible track are considered without taking the soil flexibility into account. Two well-known co-simulation approaches are used: a parallel approach, called Jacobi, and a sequential approach, called Gaus–Seidel. The definition of the subsystems, thus the place at which the entire system is split, is discussed. For the vehicle/track case, the split can be performed either between the wheel and the rail or between the rail and the sleepers. Moreover, it is shown that the output of each subsystem, either a kinematic quantity or a force, has a significant impact on the results since. It is indeed observed that, for the vehicle/track model, exchanging only kinematic quantities between the subsystem is less accurate but more stable than exchanging forces and kinematic quantities. The macrotimestep influence is also investigated and it is demonstrated that when the macrotimestep decreases, all co-simulation configuration converge to the same solution. Secondly, the soil flexibility and the vehicle influences are considered with a vehicle/track/soil model involving two different software environments: a multibody dedicated program for the vehicle and the track and a finite element analysis program for the soil. Generally, a deterioration of the results is observed in soft soil cases.