Thermal crack growth-based fatigue life prediction due to braking for a high-speed railway brake disc

• Hot spots inside brake disc were acquired using energy conversion method.
• Thermal fatigue crack was modeled by XFEM and virtual-node polygonal FEM.
• Damage tolerance method was used to evaluate the fatigue crack growth life.

Railway brake discs are the safety–critical components usually designed for up to ten years of operation. To guarantee the safety, fracture mechanics method was applied to perform the thermal fatigue crack growth simulation. Before that, thermo-physical mechanical and fracture parameters for brake discs made of an alloy forged steel were experimentally determined under different temperatures. By using novel extended finite element method (XFEM) and crack tip region meshing refinement based on virtual-node polygonal finite element method (VPM), a semi-elliptical surface crack was then inserted into a predicted macroscopic hot spot to carry out the thermal fatigue cracking analysis under consecutive emergency braking. Computational results were employed to evaluate the fatigue life and safety domain of in-service. Predicted peak temperature and calculated crack geometry were well in agreement with the experimental. Thermal fatigue crack propagation was acquired for evaluating the safety degree of the brake disc due to emergency braking mode. Finally, some remarks were provided for the design and regular maintenance of high-speed railway brake discs.