A generalized thermoelastic diffusion theory of porous materials considering strain, thermal and diffusion relaxation, and its application in the ultrashort pulse laser heating

In order to obtain the transient thermoelastic diffusion responses of porous materials heated by the ultrashort pulse laser, the focus of this work is to establish a generalized thermoelastic diffusion theory considering strain, thermal and diffusion relaxation effect within the thermodynamic framework. Firstly, we derive the governing equations of the linear generalized thermoelastic diffusion theory of porous media in the context of the thermodynamic laws. Secondly, the copper material with voids occupying a half-space heated by the ultrashort pulse laser is investigated based on the built theory. The bounding plane is assumed to be traction free and impacted by a non-Gaussian laser beam. The exact solutions of the governing equations are obtained by Laplace transformation and the numerical inverse Laplace transformation. Finally, the effect of strain relaxation factor, thermal relaxation factor, fractional order parameter, and laser parameters on non-dimensional temperature, displacement, stress, volume fraction field, and chemical potential is studied and presented graphically.