Surface displacement field by pulsed laser irradiation on metallic surfaces

摘要

This paper aims to study the working mechanism of pulsed laser generated ultrasonics on metallic surfaces as well as evaluate the pulse laser parameter effect on the generated waves. A thermoelastic model is adopted assuming that the pulsed laser works in the thermoelastic regime and illuminates on a half space metallic structure. Through Hankel-Laplace transform, the surface temperature and displacement are solved in the transformed frequency and wavenumber domain. The numerical solutions are then obtained through inverse Hankel-Laplace transform. Laser parameter effect on the epicenter displacement is studied, showing that the increase of excitation energy and decrease of laser beam radius both increase the epicenter displacement.