2022 Volume 63 Issue 4 Pages 244-250
Ultrasonic inspection of axles to detect flaws, in which shear waves are emitted into an axle at certain angles, is widely applied. However, when shear waves are obliquely incident on a boundary surface, sound beam displacement may shift the geometric reflection point parallel to the boundary surface. In this study, two types of boundary surface, that is, an axle body and a wheel seat, are targeted. The relationship between a shear-wave incident angle and sound beam displacement is derived theoretically and then confirmed using finite element calculations. The propagation behavior of ultrasonic waves while inspecting surface flaws on an axle is discussed from the viewpoint of sound beam displacement.