Crack Propagation Laws And Characteristics Analysis Of Gearbox Of High-Speed Train

Working conditions of high-speed train components have become increasingly harsh and vibration intensity of high-speed trains has also increased dramatically since operating speed of high-speed trains is steadily increasing speed in China.Gearboxes which are one of the key components to ensure the safe operation of high-speed trains have complex structures and are exposed to harsh vibration environments for a long time.Those are most likely to occur cracks which seriously affects the safe operation of high-speed trains.As a result,the crack propagation laws and characteristics of high-speed train gearboxes are analyzed in this paper.The main contents are as follows:(1)In this paper,a three-dimensional finite element model of the gearbox of a high-speed train is established in the ABAQUS software,and the key positions where the gearbox is prone to crack growth are obtained.A three-dimensional finite element model is constructed from the gearbox,and the boundary conditions are imposed on the gearbox according to the actual working conditions.The modal parameters of the gearbox in the free mode and the constrained mode are extracted according to the model built.The modal analysis of the gearbox under constrained mode is analyzed to further determine the key positions of the gearbox that is prone to crack growth.(2)Based on the extended finite element method with ABAQUS software,the stress intensity factor of the crack tip at the key positions of the gearbox is extracted.The effects of load size,crack angle and crack length on the stress intensity factor of the gearbox are studied.The results show that,the stress intensity factor also increases as the load increases;the crack stress intensity factor near the gearbox axle hole is large,and the crack is most likely to propagate when the crack angle is 120 °;as the crack length increases,the stress intensity factor increases linearly.(3)Based on the extended finite element method,the crack propagation laws at the key positions of the gearbox are studied.Based on the extended finite element method,a crack propagation model is established near the observation hole,oil observation hole and axle hole of the gear box,and the crack propagation laws of the gear box under lateral load,vertical load and composite load are analyzed.The results show that the crack at the axle hole is most likely to propagate under the lateral load of the gearbox.In the initial stage of gearbox crack growth,the equivalent stress increase value is large,and the crack growth rate is slow.When the crack propagation length reaches a certain value,the crack starts to rapidly expand,and the equivalent stress increase value becomes smaller.