| Accurate knowledge of thermal diffusivity is important for thermal analysis design. Although often assumed to respond isotropically, many polymers and composite materials exhibit thermally anisotropic responses. Materials with unknown or changing properties especially challenge the design of experiments to measure thermal diffusivities. Three thermo-optical techniques that have been proposed to measure anisotropic thermal diffusivities are the flash, thermal wave, and flash-field methods. In this work, D-optimum criteria are applied to optimize experimental parameters such as the number of temperature sensors and sensor positions in the flash method, or the number of measurements and measurement times in the other two methods. The modification of these experimental parameters can be easily achieved after an experiment for which the temperature field history of one of the specimen surfaces is measured, such as by an infrared camera. Here, each of these methods is optimized using simulated experimental temperature responses calculated for radially symmetric thermal diffusivity; noise has been added to simulate experimental data. These optimizations are then compared to determine the preferred technique for this material symmetry. |
