Research on fatigue evaluation method of high-speed train axle based on axle box acceleration

As a key safety component of the high-speed train, axle fatigue fracture would lead to major accidents such as derailment or overturning. The difficulty of axle dynamic stress test seriously enhances the difficulty of axle fatigue damage analysis. In this paper, the dynamic stress test of axle of the high-speed train was carried out, and the change of axle box acceleration was monitored in real time during the test, and the relationship between the axle stress spectrum and axle box acceleration was analyzed during the operation. The results show that the relationship between the axle cross-section equivalent stresses and the RMS values of the axle box vertical acceleration and lateral acceleration all exhibit a strong joint probability density distribution. The concept of virtual surface density of wheel-rail contact is also proposed to realize the purpose of using axle box acceleration to calculate axle equivalent force. The results quantify the relationship between axle box acceleration and axle equivalent force, provide a new method for predicting the axle cross-section equivalent force using the acceleration RMS values, and open up a new approach for structural health monitoring of axle structures in high-speed trains.