Study of Dual-Laser-Generated Surface Acoustic Waves Interacting with Multiangled Surface Breaking Cracks by Finite Element Method

摘要

In this paper we study the situation of a laser line source directly irradiating a crack modeled by a slot, which is an essential process in the scanning laser line source (SLLS) technique. The finite element method (FEM) was used to calculate the scattering of an ultrasonic wave. The propagation paths of ultrasonic waves were analyzed and corresponding waves were identified accordingly. The displacements for various slot orientations were then calculated and analyzed, and it was shown that the arrival times of some ultrasonic wave modes can be used for detecting the slot orientation. As a result, the relationship between the slot orientation and the ultrasound diffraction pattern was clarified.