Propagation of Thermal and Thermal Stress Waves in Finite Medium under Laser-Pulse Heating.

Abstract

This paper is concerned with the one-dimensional problem of thermal and thermal stress waves resulting from a suddenly applied laser-pulse heating in a finite plate, initially unstressed and at a constant temperature. The laser-pulse absorption is assumed to have Gaussian temporal profile with time, and to decay exponentially with depth. In this investigation, based on the generalized thermoelasticity, a coupling between thermal and mechanical fields is taken into account and the classical Fourie's law is also modified by adding a thermal relaxation term to the heat conduction equation to eliminate the paradox of the infinite thermal speed of the classical thermoelasticity. The numerical procedure employs the method of characteristics. The numerical calculations are carried out for two types of temperature-change input ; one is ramp-type heating on the boundary surface and the other is internal heat generation by laser-pulses. The influence of relaxation time τ0 on thermal and thermal stress waves are found for two values of τ0 and the results are shown in figures.