Research on determining the ultrasonic inspection interval of railway hollow axles based on service dynamic stress and accurate probability of detection on cracks

The implementation of recurrent ultrasonic inspections serves to guarantee the safety and quality of hollow axles in high-speed trains. Nevertheless, there is an urgent requirement to optimize the existing empirical-based inspection intervals. This paper, based on the principle of damage tolerance, puts forward a comprehensive and scientifically rigorous approach to determine the optimal ultrasonic inspection interval for railway hollow axles. In this study, a remaining life analysis model for axles with cracks was developed with the integration of the factors of crack propagation properties of the axle material, service stress spectrum in critical sections of axles, and the press fit effect of wheel and axle assembly. By integrating the remaining life of the axle with the probability of detection (POD) curves obtained from experimental ultrasonic testing equipment, a comprehensive methodology for determining the optimal ultrasonic inspection interval for railway hollow axles was established. This research provides support for optimizing the ultrasonic inspection intervals of high-speed train axles.