Modelling of laser-material interaction using semi-analytical approach

Abstract

In this paper different aspects of laser-material interaction were considered. Semi-analytical method was developed and applied to analysis of spatial and temporal distribution of temperature field inside bulk materials. In particular, cases with cylindrical geometry, finite diameter and infinite length as well as cylindrical geometry, finite diameter and finite length were considered. For solving the governing partial differential equations (PDEs) the Laplace transform and the Fourier method of variables separation were used. In this way instead of the original governing PDEs, ordinary differential equations were solved. Particular solutions of the ordinary differential equations were used for evaluating the general solution, which was expressed in terms of series of particular solutions. The unknown coefficients in the series of particular solutions were determined using the boundary and initial conditions. The laser-material interaction was represented using the thermal model. These interactions for the cases of the high power laser in pulse and continuous regime were analysed. The incident intensity of laser radiation was under critical intensity.Using these methods the temperature field distribution was obtained in the Laplace transform domain. The convolution integral and the Green function were used to determine the temperature field in time domain. General semi-analytical methods and numerical solutions of appropriate transcendent equations were considered and numerical results for Al specimens were presented. The influences of laser beam parameters to the temperature field distribution and isothermal curves inside the bulk material were evaluated.