The influence of plastic deformations on growth of subsurface rolling contact fatigue cracks in railway wheels

Artikel i vetenskaplig tidskrift, 2006

A subsurface rolling contact fatigue crack in a railway wheel is studied. Stress and strain fields are evaluated by elasto-plastic finite-element simulations. The robustness and validity of the numerical model are investigated. A suitable measure to characterize crack propagation is then sought. Numerical results show that the effect of crack tip plasticity is small for cases studied, indicating that linear elastic fracture mechanics approaches are applicable. Further, the magnitudes of the stress intensity factor in mode I, KI, are negative implying crack closure. Motivated by these findings, the stress intensity factor range in mode II, ΔKII, is employed as a measure of crack propagation. Finally, studies are carried out to quantify the effects of altered contact load conditions and crack face friction.