Research on monitoring method for crack depth of railway hollow axle during bench test.

Hollow axles are critical safety components for high‐speed trains, and the operational safety of the axle is ensured by combining infinite life design and damage tolerance analysis based on ultrasonic testing. The establishment of the ultrasonic inspection interval requires the axle bench test, but it has been a challenge to obtain the initial crack at a determined depth. This paper proposes a method for predicting the transverse crack depth of axles by combining a full‐scale axle bench test with simulation analysis. The monitoring of crack depth is achieved by measuring the cracks on the axle surface. The crack propagation test was conducted to validate the prediction method with good results. The test results demonstrate the potential of crack monitoring methods in axle crack monitoring and provide new ideas for axle safety monitoring. Highlights: A method to analyze the evolutionary pattern of axle cracks is proposed.The morphology of axle cracks tends to be consistent and flattened gradually.The path of crack propagation is the path of the fastest crack area growth.Axle crack depth can be obtained in real time by the measurement of the crack length. [ABSTRACT FROM AUTHOR]