Quantcast

Inverse estimation of the material parameters at metal surface irradiated by laser pulse

Research paper by Jiajia Zhang, Juan Bi, Guibo Chen

Indexed on: 22 Oct '16Published on: 21 Oct '16Published in: Optik



Abstract

Based on nonlinear conjugate gradient theory, a new inversion algorithm is proposed to estimate the reflection and absorption coefficients for the surface of metallic materials irradiated by pulsed laser. Firstly, the basic principle of direct and inverse problems of laser heating is showed, and analytical expression of sensitivity coefficient is obtained due to the analytical solution of direct problem. Then, the sensitivity analysis is carried out, and the change of the relative sensitivity coefficient is investigated. The algorithm is verified by the specific example, and the best condition of the convergence is analyzed. Finally, the influence of the iterative initial values on the convergence of the iterative process and the variation characteristics of the inversion results in the iterative process are investigated with the special model. Research results can be used for analysis of material properties and selection of parameters in the field of laser processing, and also can provide an effective means for the evaluation of the effect of laser damage, it has important theoretical and practical significance.