Finite element simulation of phased array laser-generated surface acoustic wave for identification surface defects

A physical model of phased-array laser source is proposed for detecting surface defects. In order to verify that the phased array laser system with the element spacing D=0.1mm can effectively detect the surface defects at different depths, optimize the parameter performance of the finite element simulation by comparing the amplitude and spectrum characteristics of ultrasonic wave generated by phased array laser source but different element spacing. When the depth of surface defect changes from 0.5mm to 2.5mm, the amplitude of Rr-wave gradually increases, the amplitude of Tr (Transmitted wave) gradually decreases and the peak time of the transmitted wave gradually increases. This method can be eeffective applied to detect the depth of surface defect.