Analytical solution for thermal stresses during the laser pulse heating process

Abstract

Abstract

Laser pulse heating of surfaces initiates thermal stress generation in the region irradiated by a laser beam. Depending on the level of thermal stresses, structural changes occur inside the substrate material. In the present study, laser step input pulse heating and thermal stress generation are considered. The governing equations of heat conduction and momentum are solved analytically. In the analysis, two cases are considered, namely a stress-free surface (σx = 0 at x = 0) and a zero stress gradient at the surface (ϑσx/ϑx = 0 at x = 0). The temperature and stress fields are computed using the closed-form solution, which is derived using a Laplace transformation method. It is found that considerably high stress levels developed at some depth below the surface. The stress-free surface condition suppresses a rise in thermal stress in the surface vicinity of the substrate material, while the zero stress gradient condition at the surface results in compressive stress levels in the surface vicinity.