Accurate And Fast Evaluation Of Orthotropic Thermal Diffusivity Within A Membrane: A Theoretical Approach

In this paper, we propose a theoretical investigation of several configurations based on the infrared photothermal radiometry in order to estimate the thermal diffusivity of isotropic and orthotropic membranes. The front-face and rear-face experimental configurations are considered and show complementary results. Analytical approximations based on characteristic values of the simulated variations of the observed physical quantities, such as the phase or the amplitude, as well as the geometrical parameters are presented. Those approximations are reliable on a large range of thermal properties that make them useful for a large variety of applications. The case of semi-transparent membranes is also treated theoretically, which requires the implementation of non-linear least square minimization to estimate the in-plane thermal diffusivity.