Macroscopic defects below the surface of a railway wheel may give birth to subsurface cracks, which may propagate and cause catastrophic wheel failures. The behaviour of subsurface cracks under rolling contact conditions is the main issue of the current paper. A two-dimensional FE-model of a crack in a railway wheel, subjected to a moving Hertzian contact load, has been developed. Elasto-plastic material with non-linear kinematic hardening has been employed in the model and the deformation of the subsurface crack has been studied. It has been shown how rolling contact loading introduces a crack edge shearing, causing relative horizontal displacements between the upper and lower crack edges. Further, it has been shown how various parameters, such as contact load magnitude, contact geometry, crack geometry, crack location and crack face friction, will influence the response. An important finding is that, high contact pressures introduce marked residual horizontal deformations between crack edges. The effects of the other parameters are less severe for the cases studied. The results also show how friction and plasticity influence the deformation behaviour indicating e.g., the importance of crack tip plasticity. The practical implication of the current study is primarily to act as a foundation for subsequent studies of the propagation of subsurface cracks in railway wheels. Knowledge of this phenomenon is vital in the design of railway wheels as well as in the planning of maintenance and inspection intervals.
Sub-surface crack face displacements in railway wheels
2003
7 Seiten, 10 Bilder, 9 Quellen
Conference paper
English
Sub-surface crack face displacements in railway wheels
British Library Conference Proceedings | 2003
|Engineering Index Backfile | 1940