Thermal diffusivity measurement of ring specimens by infrared thermography

The thermal diffusivity of solid materials is usually measured with the well-known flash method. In the traditional setup, the tested specimens have the shape of a small disc. However, several industrial applications need to test different typologies of samples. This work is focused on ring specimens, that are widely used as joints or sealants in various applications. The goal is investigating the possibilities and limitations of the flash method, applying minimum adjustments to the traditional experimental setup. A preliminary numerical study is conducted with the creation of a finite element model. Firstly, the model is checked with the standard case of a full disk. Then the simulation investigates the case of an aluminum oxide ring, that is taken as the reference case to determine the reliability of the proposed technique. After the simulation, an experimental measurement is performed on the aluminum oxide ring reference case. Several samples are tested and useful information on the practical feasibility of the experimental setup are collected. The obtained thermal diffusivity values fall into the expected range for the material, confirming the validity of the suggested method.