Auteur : Stéphane André , Norbert Renault, Yves Meshaka, Christian Cunat

Journal : Continuum Mechanics and Thermodynamics

This paper aims at presenting the complete metrological problem associated to the thermomechanical characterization of materials. With this purpose in view, we first present a model based on irreversible thermodynamics that allows straightforward formulation of the set of the required state laws. Then, the state law, which links both entropy and temperature variables, is used within an entropy balance. It leads to the heat equation allowing for the identification of the different contributions involved in the apparent Thermomechanical Heat Source (THS). This THS is measured during the tensile experiment of a semicrystalline polymer, thanks to the monitoring of in-situ infrared temperature fields and the subsequent application of numerical reconstruction algorithms. Both stress-strain and THS-strain curves obtained experimentally over the same representative elementary volume are used simultaneously to identify the parameters of the behavioral model. The results first showthat themodel is able to describe the measured THS. Secondly, they allowfor a clear analysis of various thermomechanical contributions (thermoelastic effect, total pure intrinsic dissipation, entropic couplings contribution reflecting microstructure transformations), which can be very helpful in understanding microscopic deformation phenomena.

Mis à jour le 14/10/2011