| In recent years, laser technology has rapidly developed and been widely used inmany fields, particularly in space industry. Mechanisms of the interaction between laserand materials are not only the basis of choosing laser materials but also the importanttheory in designing laser weapons, and then the study on the damage mechanisms oflaser irradiated materials became a new subject of scientific research.This thesis first summarizes the development background of laser technology andthe thermo-mechanical coupling effect of laser irradiation materials, and then simulatesthe thermo-mechanical coupling effect in long-pulsed multi-spectral laser irradiationwindow material ZnS by using the Fourier heat conduction formula. Main simulationresults are: in irradiation region, ZnS absorbs the laser irradiation energy and then thetemperature is increased. Out of the irradiation region, the temperature is less influenced,and then a temperature difference is generated. The material’s deformation due todifferent expansion or contraction in different regions originated from the temperaturedifference results in thermal stress, which is determined by the temperature conditions.Accordingly, the material’s mechanisms are significantly influenced by the irradiation.Under the combined effect of the temperature difference and the material’s expansion orcontraction, the principle stress increases with increased surface depth of the laserirradiation. The stresses of compression and tension forms become to each other, andthen the equivalent stress exhibits a wave property in the thickness direction. The wavepropagates away with time accompanied by increased amplitude, which is reflected bythe stress field. Since the laser’s amplitude exhibits a Gaussin form in space, theequivalent stress has maxima in the irradiation spot, where the material is easilydamaged. The damage comes from the stress resulted from temperature increase due toirradiation but not the melting one. |
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