X-FEM crack propagation under rolling contact fatigue accounting for actual residual stresses in the rail
Résumé
For a more cost efficient railway system, it is essential to optimize the maintenance of rails and the scheduling of the rail replacement operations. To support this process a numerical modelling tool has been developed thanks to a long-term collaboration between railway organizations (SNCF, RFF, RATP), rail producer (Tata Steel) and research institutes and universities (INRETS, LMS, MECAMIX, INSA) within the IDR2 consortium (Initiative for Development and for Research on Rail). This modelling starts with a dynamic simulation of the vehicle rolling on a track, from which the cyclic mechanical state of the rail is calculated by means of a 3D finite element simulation and an original and time-cost efficient direct stationary algorithm. Finally, a fatigue analysis of the rail is performed using the Dang Van criterion. The modelling tool has been recently completed with the simulation of the crack propagation in the rails. A two-scale frictional contact fatigue crack model developed within the X-FEM framework is used to solve the crack problem. Using this approach, contact and friction between the crack faces is taken into account in the simulation. Realistic residual stresses, using dedicated software developed by SNCF are introduced in the propagation simulation via projection of the asymptotic mechanical fields. Crack growth is performed taking into account this permanent non-uniform field.2D results and 3D preliminary results are shown in this paper showing the high influence of the residual stresses on the crack growth rate.
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