Simulation analysis of ultrasonic inspection of hollow axle with different segments

Hollow axle has replaced the traditional solid axle in high-speed trains due to the increased operational speed. The ultrasonic inspection on hollow axles must be conducted to ensure the safe operation of high-speed trains. The hollow axle can be artificially divided into different segment based on the shape and size of different axle segments including the transition arc section. Different inspection results from these axle segments can be obtained due to the different sound path and the different dimension of the transition arc. Simulation models about different axle segments were established by means of COMSOL Multiphysics. The difference of the simulation results, from different axle segments tested by probes with different angles and directions, are discussed, which may provide guidance for the setup of gate and selection of probes while carrying out actual ultrasonic inspection on hollow axle.