Abstract
A practically suitable and sensitive technique for quantitative nondestructive evaluation of small cracks is presented here. The technique is based on a back wall echo of the shear wave propagating in the solid containing the cracks. In contrast to the normal and angular incidence of longitudinal wave, the effect of the oblique shear wave on the ultrasonic response due to a crack is investigated. The testing is performed to predict an optimum angle of evaluation which provides the superiority of the method compared to the well-known usual techniques.
