Closed form solutions for thermal stress field due to non-equilibrium heating during laser short-pulse irradiation

Non-equilibrium heating in the lattice sub-system results in high temperature gradients in the surface region. This in turn causes thermal stress waves propagating into the substrate material. In the present study, a closed form solution for thermal stress developed in the substrate material due to volumetric pulse heating is presented. The stress free and stress continuity boundary conditions at the surface are incorporated in the closed form solutions. It is found that thermal stress wave is tensile in the surface region and it becomes compressive at some depth below the surface for stress free condition at the surface; however, it remains compressive for the condition of stress continuity at the surface.