Estimation of Surface Absorptivity and Surface Temperature in Laser Surface Hardening Process

Abstract

A two-dimensional, quasi-static, inverse heat conduction problem (IHCP) is implemented to investigate the absorption efficiency of surface coatings in laser surface hardening process. The analysis of IHCP includes the utilization of the method of direct sensitivity coefficient and the measurement of interior temperatures nearby the laser heating surface. The results shows that the estimation of surface absorptivity generally agrees with that observed by experimental works. It is realized that the different kinds of coating make influences on the surface absorptivity as well as surface temperature significantly. Furthermore, the power density and scanning speed of laser beam to control the quality of surface hardening may be determined based on the informations of heat flow in the workpiece.

A prediction of the friction factor for the forging process

“…These two new bracketing points are given laser surface treatment. [12,13] One of the main differences as follows: between direct analysis and inverse analysis is that the latter treats the unknown coefficients in the boundary condition m 1 ϭ (1 Ϫ )m L ϩ m U [19] as dependent variables and the field variables as independent m 2 ϭ m L ϩ (1 Ϫ )m U [20] variables. The inverse method usually involves a complicated mathematical derivation.…”

“…Thus, region can only contain a quarter of the entire original domain with appropriately applied symmetrical conditions. [12] (4) Boundary conditions:…”

“…The friction ing these equations into Eq. [12] yields the discretized factor is continually updated until the objective function functional.…”

“…The objective function is introThe solution of the original boundary-value problem gives duced as Eq. [12] a stationary value, that is,…”

Real-time photothermal imaging and response in pulsed dye laser treatment for port wine stain patients

“…The main objective of this study is the analysis and evaluation of skin temperature during laser application which will, in turn, assist medical practitioners in assessing and treating the reaction of skin to laser energy. [25] A heat transfer analysis using the thermal wave equation helps us to learn the importance of the thermal wave theory of photothermal effect. Using an infrared thermal image instrument and with the thermal changes obtained using thermal wave equations, the reliability of th e analytic solution can be ensured.…”