Quantitative Evaluation of the Flaw Echo of Railway Axles in Consideration of Contact Pressure with a Wheel

Abstract

For railway axles, the wheel seat is periodically inspected by ultrasonic testing. When the ultrasonic axle inspection is performed while the wheels are mounted, the flaw echo height varies depending on the fitting condition. When the inspection is performed on an in-service axle, the echo height also varies under the influence of the bending load acting on the axle due to the car weight. In this study, the variation in echo height due to the contact pressure with a wheel was quantitatively evaluated by simulation of ultrasound propagation. Moreover, the echo-height variation during cyclic rotating bending in a full-sized wheelset was investigated experimentally by studying variation in normal stiffness at the axle-wheel interface.

<b>Evaluation of Influence of Reflection Point Shift on Axle Surface in Ultrasonic Flaw Detection</b>

“…If this axlewheel interface is treated as a perfect bonding surface, no reflection waves occur at the interface and the reflection behavior of ultrasonic waves cannot be expressed. Therefore, we applied a spring interface [4][5][6] to the axle-wheel interface, and in this manner, the sound beam displacement at the spring interface was investigated. Here we investigated a periodically cracked interface [7] shown in Fig.…”