Experimental and numerical investigations of wedge waves and its dispersion behaviors propagating along wedges

摘要

In this paper, both numerical simulation employing finite element method (FEM) and experimental work by using laser ultrasound technique was done to investigate the wedge wave modes in wedges with different apex angles. We focused not only on the wedge waves propagating along the wedge tip, but also the dispersion characteristics of the wave modes. Firstly, finite-element method was used to simulate the laser induced wedge waves and different orders of wedge wave modes could be clearly observed for different apex-angle wedges with non-dispersion. Then pulsed laser excitation and optical deflection beam method for detection was built to investigate the wedge waves experimentally. The wedge waves at different positions were recorded by scanning the excitation laser source along the wedge tip and the dispersions and phase velocities of the wedge waves were obtained by using 2D Fourier transformation method. The numbers of wedge wave modes were observed on wedges with different apex angles is in good agreement with Lagasse's empirical formula and our numerical simulation.