Hot strip method: application to thermal characterisation of orthotropic media

International audienceThis study deals with determination of the thermal conductivity tensor for orthotropic media and more specifically for multilayers with isotropic thermal characteristics in the planes parallel to the layers. The work described has been conducted using two ordinary experimental devices: a device based on the hot-wire method and a device based on the hot-strip method. Hot-wire measurements give the thermal conductivity in the planes parallel to layers. Introducing this value in a model adequate to describe orthotropic behaviour and using an appropriate identification method, hot-strip measurements then give the transverse thermal conductivity. The validity of this approach is demonstrated by the results obtained on a stratified medium with known thermal characteristics. Then, transverse thermal measurements were made on a non-woven wood fibre insulator

Prediction of effective thermal properties of fibrous material from 3D tomographic images

Fibrous composites materials are commonly used for thermal insulating purpose and cover a wide range of applications, from high temperature to building insulators. Their effective thermal properties strongly depends on the fibers arrangement, i.e. fibers orientations and number of fibers contacts., which are a consequence of the manufacturing process. Furthermore, local thermal conductivity of the fiber are often anisotropic, as it is the case in natural fibers for example. Thermal optimization of such materials is a major industrial stake and it requires tools to study the complex relation between the materials microstructure and the effective properties. In this work, we make use of tridimensionnal images of the fibrous microstructure to quantify some aspects of the microstructure, like fibers local orientations. These information are then used to compute effective properties directly on an representative elementary volume (REV) of the real structure, within the framework of the volume averaging method applied

De la critique des dispositifs à l’intermédialité pour approcher les productions artistiques : bilan des travaux du séminaire Intermedialidades (Université Toulouse-Jean Jaurès, France)

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