Inverse Estimation Of Surface Temperature Of Object Heated By Laser Based On Conjugate Gradient Method

In recent years,with the rapid development of laser technology,the research field of the interaction between laser and materials has been studied in depth by researchers.The thermal effect of laser irradiated materials,as the basis of laser processing,heat treatment and laser damage effect,is attracting more and more scholars' attention.In this paper,firstly the temperature rise model of the material irradiated by laser is established based on heat conduction theory,and the analytical solution of the temperature fields of the material is obtained by using Laplace transform method.Then the sum of squared residuals between the measured temperature and the calculated temperature data is selected as the objective function,and estimate of material parameters on the objective function minimization by using the conjugate gradient method.At last,three types of materials are selected for laser irradiation,which are homogeneous materials,the two-layer system materials with constant surface absorption and temperature dependent front surface absorptance.The inverse estimation of material parameters is carried out.Substituting material parameters into the analytical solution yields the surface temperature.The results show that the presented algorithm in this paper can well effectively estimate the material parameters,and then calculate the temperature rise of the material surface.And the algorithm converges quickly and the inversion precision is high.The work in this paper has certain reference significance for the temperature or parameter inversion in the process of laser damage and laser processing.