Dynamic fatigue damage calculation for a high-speed train bogie frame considering the three-dimensional gear meshing

A three-dimensional rigid-flexible coupling model of a high-speed train has been developed incorporating both the elastic bogie frame and the gear meshing within the drivetrain system. Notably, both the wheel polygonisation and dynamic nonlinear internal excitation forces induced by the time-varying gear meshing stiffness and errors of the gear meshing are systematically taken into account. By virtue of the finite element scheme, the real-time and time-varying cumulative fatigue damage of the bogie frame is achieved based on the rainflow method and Miner's damage summation rule. Numerical results demonstrate that the impacts of nonlinear internal excitation forces and wheel polygonisation on the fatigue damage of the bogie frame are significant. Compared to the case without nonlinear internal excitation forces, the fatigue damage at some critical positions of the bogie frame drastically increases, specifically, the damage of the most dangerous position increases by approximately 106.09%. Whether the dynamic internal excitation forces are exit or not, the fatigue damage of the bogie frame increases with the increasing amplitude of the polygonal wheel. The effect of nonlinear internal excitation forces on the fatigue damage of the bogie frame is more pronounced at lower amplitudes of the polygonal wheel.