Simultaneous Identification of Thermal Diffusivity, Thickness, and Heating Center Point Based on Surface Temperature Variation Excited by Laser-Spot Heating

An infrared thermographic technique was developed for identifying the thermal diffusivity from temperature variation data of the specimen surface. Laser-spot heating is applied to the specimen surface for a certain period, and then, temperature variation in the surface is measured using infrared thermography. Since analytical solution for the temperature variation is expressed in terms of parameters including the thermal diffusivity, thickness and heating point position, the parameters are identified by fitting the analytical solution to the measured data. The developed technique was applied to a ceramic specimen for verification. It was shown that the thermal diffusivity can be identified with high accuracy if the thickness and heating point position are known in advance. Furthermore, it is confirmed that the thermal diffusivity, thickness, and heating point position can be simultaneously estimated with acceptable accuracy.