Abstract
The deformation of solid materials is accompanied by irreversible dissipative effects. Irreversibility, whose nature depends on the behaviourof material, results in an intrinsic dissipation of mechanical energy. It may also be due to thermal dissipation induced by heat diffusion andgenerated by thermomechanical couplings. The temperature variations produced by these various volume heat sources depend not only on thematerial diffusivity, but also on the boundary conditions with the surrounding. Thus, the thermal data are not completely intrinsic to materialbehaviour. Techniques of infrared image processing were then investigated to take into account the regularising effects of heat diffusion, andto estimate, under certain conditions, the distribution of sources during a deformation process. Having briefly reminded the thermodynamicframework used to interpret the experiments, the numerical methods of infrared image processing will be presented. Finally, the potentialitiesof this approach will be illustrated through several examples. In the case of thermomechanical homogeneous tests, it is possible to draw upcomplete energy balance useful for developing behavioural constitutive equations. When nonuniform deformation processes arise, infraredand speckle image processing may be associated to study dissipative and kinematic effects of localisation phenomena.