Thermoelastic stresses in a bonded layer due to repetitively pulsed laser radiation

Abstract

A method is presented for the calculation of thermoelastic stress and displacement fields in a bonded layer that absorbs thermal energy from a repetitively pulsed laser in its surface plane. A function with three adjustable parameters is used to simulate the temporal variation of each pulse while the radial intensity distribution (or mode structure) of each pulse follows a Gaussian profile. The pulse duration is of the order of the characteristic time for heat to diffuse across the layer thickness, and hence axial heat conduction cannot be neglected. Stress and displacement components due to heat absorption from three successive pulses are calculated and examined specifically at the free surface, at selected points within the layer, and at the bonded interface. The stress components at the bonded interface are also examined over a range of layer thicknesses to illustrate key differences between the thermoelastic responses of thin and thick layers.