Based on actual load conditions,the transient temperature field and thermal stress field of rail wheel under the conditions of service braking,emergency braking and ramp braking are calculated by means of the finite element theory.The sub-model of crack propagation on the edge of wheel web hole is established,and fatigue crack propagation property of non-worn wheel and worn 20mm wheel is simulated and analyzed.As a result,the inner side of web hole is in a prolonged condition of tensile stress,while the outside of web hole is in the condition of compressive stress,where the value of tensile stress is maximal under ramp braking.Fatigue crack growth rate on the edge of web hole is the fastest under the combined action of mechanical load,ramp braking and curve running.Under same braking condition,the applied stress value and crack growth rate of worn wheel web hole is much larger and quicker than that of non-worn wheel.In a maintenance period (1.5 years),for the non-worn wheel,the allowed upper value of crack propagation is defined as 15mm.For the worn 20mm wheel,it must be stopped using when the crack or damage is observed in condition of safety reliability.
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