Thermal Stresses Due to Exponentially Decaying Laser Pulses and a Convection Boundary at the Surface
B.S. Yilbas and N. Al-Ageeli
Laser pulse heating of surfaces results in high temperature gradients in the region irradiated by the laser beam. This, in turn, results in thermal strain and stress fields. In the case of laser gas assisted processing, convective boundary conditions arise on the surface of the substrate material. Consequently, an investigation into laser induced thermal stresses is essential. In the present study, laser pulses decreasing exponentially with time and with a convective boundary condition at the surface is considered and a closed form solution for thermal stress distribution obtained using a Laplace transformation method. Steel is employed to simulate the temperature and stress fields. It is found that the influence of the heat transfer coeffcient on the temperature profile is significant at a dimensionless heat transfer coeffcient of 0.0202. The thermal stress is tensile in the vicinity of the surface and becomes compressive at some depth below the surface. A thermal stress wave is developed for a dimensionless heat transfer coeffcient of 0.0202.