Using multi-core architectures to solve the wheel-rail contact problem

The forces exchanged between wheel and the rail are fundamental in order to study the railway vehicle dynamic. These forces arise from the non linear combination of profile contact and friction and their calculation can be performed using iterative methods which require important calculation time. Simulation of railway vehicle dynamic takes therefore large calculation time or simplified contact models are needed. This becomes critical especially in case of real time simulation. Recent development of CPU based on multi-core processor makes possible to distribute the calculation of contact forces and the vehicle dynamic problem over different cores, reducing the calculation time. This work describes the strategies adopted to perform parallel distributed calculation starting from the RTCONTACT code, developed at Politecnico di Torino during the last years. According to the proposed approach, the contact problem is solved using one core for each wheel, while one or more cores can be used to solve the vehicle dynamics. An example of application of the contact code, distributed on different cores, is shown during evaluation in a real-time environment of the wheel and roller profile evolution on a scaled roller-rig.