Design of Experiment for Thermal Diffusivity Measurements of Composite Material with Orthogonal Anisotropy

This article deals with simultaneous measurements of three mutually orthogonal thermal diffusivities of a material with orthogonal anisotropy using the flash method. Unlike the conventional flash method, the modified measuring technique considers pulse heating over a rectangular area of the front face of a wall-shaped sample of an orthotropic composite material. The thermal diffusivities are calculated analyzing the temperature rise versus time evolutions when measured simultaneously at various positions on the sample surface. This article presents a data reduction method that enables estimates of the thermal diffusivities for the three principal axes. The theory takes into account heat losses from the front and rear faces. The results of an experimental design analysis are discussed.