Finite element simulation of laser generated ultrasound waves in aluminum plates

Abstract

The Laser-Ultrasonic technique uses laser energy to generate ultrasound waves in various solids. This technique allows inspecting large structures. The generated ultrasound wave form is affected by features of laser pulse (wavelength, pulse duration, power density). The goal of this paper is to study the effects of laser parameters (rise time and beam radius of laser) on the laser generated surface acoustic waves in an aluminum plate. The results obtained from the finite element model of laser generated ultrasound are presented in terms of temperature and displacement. At first, the transient temperature field can be precisely calculated by using the finite element method. Then, laser generated surface acoustic wave forms are calculated in aluminum plate. Results from numerical simulation are compared with other references; the accuracy of the method is proved accordingly. In this simulation the sequential field coupling is used. Simulation results show that the laser parameters have a significant influence on the ultrasound waves and will be able to be utilized to choose best experimental parameters of laser.