Transient thermoelastic response analysis of porous composite structures ablated by the ultrashort pulse laser considering absorption mechanisms of plasma plume

The absorption mechanisms of plasma plume (such as inverse bremsstrahlung, photo-ionization and Mie absorption) to ultrashort pulse laser have significantly influence on efficiency and quality of laser machining. This motivates us to establish the spatial nonlocal generalized thermoelastic model with plasma absorption mechanisms. Based on the new model, the porous sandwich composite material with perfectly bonded interface is researched. The two outer layers are made of copper and two boundaries are heated by the picosecond pulse laser. The middle layer's material properties are proportionate to those of the outer layers. By using the Laplace transformation and inverse Laplace transform, the governing equations that incorporate spatial nonlocal parameter, strain and thermal relaxation factors are solved. The transient responses, such as temperature, volume fraction field, etc., with different laser parameters, material characteristic parameter and absorption mechanisms of plasma plume are obtained and illustrated graphically.