抄録
A new laser system to generate the focused Lamb wave using the arc array slit is proposed. In this system, spatially expanded Nd:YAG pulse laser is illuminated through the arc array slit on the surface of a sample plate to generate the Lamb wave of the same pattern as the slit. Then the generated Lamb wave is focused at the focal point of which distance from the slit position is dependent on the curvature of slit arc . The basic performance of the proposed method was predicted by simulations and verified by experiments. Especially in simulations, the effects of number of array and the slit width to the intensity at the focal point were investigated. The results of defect-detection experiments showed that the proposed method had better spatial resolution than the conventional line array slit in the detection of linear and circular defects on an aluminum plate.
