Wheel tread damages a numerical study of railway wheel tread plasticity under thermomechanical loading

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Wheel tread damages a numerical study of railway wheel tread plasticity under thermomechanical loading

Vernersson, T. / Caprioli, S. / Kabo, E. / Hansson, H. / Ekberg, A.

The current study has demonstrated the influence of the combined mechanical and thermal loading on the material response (in the wheel rim). It has been shown that it is not possible to reduce the problem to 2D for cases of plastic deformations because such a simplification will result in unrealistically high strains stemming from the (unrealistically) restricted thermal expansion. Three-dimensional elastoplastic numerical simulations were then adopted. A purely mechanical analysis showed how an applied traction corresponds to a most stressed material point at the wheel tread. This is in accordance with what has been found from purely elastic analysis. A relatively moderate thermal loading with a temperature increase up to 300 deg C was seen to have an effect mainly in that it shifts the response towards a more tensile state of strain. This shift is mainly an effect of the thermomechanical loading and not of the somewhat decreased yield limit at higher temperatures. The latter would rather give the opposite effect, in particular in the case of pure rolling. A consequence is an increase in the magnitudes of effective strains under tractive rolling. In particular, an increased temperature in combination with a high traction leads to a massive increase in plastic strain magnitudes and subsequent plastic deformation at the surface.