Evaluation of fatigue damage by surface SH wave in carbon steel

The majority of the accidents for machines and structures is the cause of the fatigue fracture, so many investigations on the nondestructive inspection have been carried out about the fatigue fracture. As one of the methods, the investigation by using a diffracted surface SH ultrasonic wave (a horizontally shear wave) technique have been started recently. In the present study, the received wave forms during the fatigue process with rotating bending tests of low carbon steel have been measured by using a diffracted surface SH wave technique under three kinds of stress amplitude and two kinds of ultrasonic probe. It was found that changing of the wave area and of the propagation time of the received wave forms depend on number cycles of fatigue, a stress amplitude, fatigue properties and the kind of probe. From these results, the fatigue damage was evaluated in the subsurface of low carbon steel.