Speaker
Description
This presentation follows earlier work on the simultaneous estimation of the thermal conductivity components and heat capacity of orthotropic materials. The original innovation lays in demonstrating the feasibility of performing an experiment capable of simultaneously visualizing, using a single infrared camera, four faces of the same parallelepiped orthotropic material: the heated surface and three other surfaces in the principal directions. A 3D analytical model was developed using Fourier-type integral transformations in the three spatial directions. Tests estimating the thermal properties of an arbitrary material were then performed using simulated and noisy temperatures derived from the direct model A key feature is that the functional considered temperatures in all three directions simultaneously. Furthermore, the minimization relied on temperatures integral transformed over the surfaces. Bayesian inference was used for the estimation. Since computation times can be long with this method, a weighted ranking of each mode was used to reduce the number of modes required. This presentation elaborates on the three experimental, numerical, and estimation aspects. A sensitivity study is first proposed to validate the use of a multi-observable functional. Subsequently, estimation tests are presented using simulated data, first without and then with noise, via the COMSOL Multiphysics® finite element software for a material with balsa properties. Balsa is thus tested experimentally, and the resulting temperatures are transformed using the same protocol in order to estimate the three thermal conductivity components and the heat capacity. The results are then discussed, particularly the direct model and the boundary conditions, given the significant computation time due in part to the large number of pixels specific to each face.
