Papers by Author: Toshihiko Abe

Abstract: Fatigue cracks and SCC (Stress Corrosion Cracking) on a back surface were detected, and the shape of cracks were evaluated using a surface wave generated by focusing angle beam ultrasound. Internal ultrasonic images showed a little shorter length than optical images. Cross section of the fatigue crack and internal distribution of complicated shaped SCC were estimated.

Abstract: The propagation characteristics of the back-reflected Rayleigh surface wave in chemical vapor deposit (CVD) diamond coated specimens were investigated experimentally using the ultrasonic backward radiation measurement. The deliberated delaminations produced between the coating layer and the substrate decreased Rayleigh surface wave velocity. This initial experimental result obtained in the present study demonstrates the high potential of the backward radiated ultrasound as a tool for nondestructive evaluation of very thin CVD diamond coating layer.