Multi-scale finite element model to describe wear and rolling contact fatigue in the wheel-rail test rig

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Multi-scale finite element model to describe wear and rolling contact fatigue in the wheel-rail test rig

Pletz, Martin / Daves, Werner / Yao, Weiping / Kubin, Wilhelm / Scheriau, Stephan

In this work, a methodology for applying loads, obtained from a three-dimensional (3D) wheel rail contact model, on two dimensional (2D) models is developed and local phenomena such as wear and crack propagation are investigated. This method is illustrated for the case of a test-rig of the voestalpine company, where one wheel is repeatedly rolled over a rail. In the finite element 3D test-rig model, the contact patch is calculated. From the gauge comer to the top of the rail the contact pressure, shear stresses and also the direction of shear and slip changes are examined. Two special points on the rail are selected, in which the contact pressure, the sliding direction, the contact patch length (in sliding direction) and the slip are evaluated. These values are applied in 2D models for the local loading of the rail. In one of them, the "crack model", the crack tip driving force on an existing crack is calculated. In the other one, the "roughness model", a measured roughness of both wheel and rail is modeled and the plastic deformation of the surface is studied in the region of the asperities for the first cycles of loading.