Numerical study of the mechanical deterioration of insulated rail joints

Numerical simulations are performed to study plastic deformation and fatigue impact of an insulated joint. The simulations feature a sophisticated constitutive model capable of capturing ratcheting under multi-axial loading conditions. Calculation results are presented in the form of effective strain magnitudes, plastic zone sizes, and multi-axial low cycle fatigue parameters. The simulation results indicate that the main damage mechanism at insulated joints is ratcheting and not low cycle fatigue. A parametric study quantifies effects of increased vertical and longitudinal load magnitudes, as well as the effect of an increased insulating gap. In particular, longitudinal loading is indicated as being severely deteriorating for the rail in the vicinity of the joint. Finally, the effect of rail edge bevelling is assessed and found to be small for the case studied.