This paper presents an infrared data processing developed to analyse the calori®c manifestations accompanying elastoplastic transformation during tensile tests. The surface temperature images are provided by an experimental set-up essentially made of a testing machine coupled with an infrared camera equipped with a home-made numerizer. The`inverse' passage from temperatures to heat sources is detailed in the case of¯at and thin parallelepipedic samples. The infrared image processing, based on FourierÕs techniques, was checked using spectral solutions of the heat equation in the case of realistic examples close to experiments. Numerical simulations are shown which attest coherence and eciency of the method for several heat source distributions and dierent sets of noisy data. The method is then applied to experimental data ®les coming from tensile tests on mild steels at the room temperature. Sudden dissipative eects due to the propagation of the L uders bands during the plastic plateau can be observed. Then, during the strain hardening, gradual and precocious concentrations of dissipation are shown; they herald the local necking of the sample. Finally, the interest of such experimental results is brie¯y discussed by referring to the specialised literature dealing with localisation phenomena and behaviour identi®cation.

The fatigue of dual phase steel was examined in terms of calorimetric effects in order to match the energy manifestations of fatigue and constitutive equations drawn up in a thermomechanical framework. A simplified method, assuming a homogeneous fatigue test, is proposed to determine heat source development from a temperature field provided by an infrared camera. Thermoelastic and dissipative sources were then separately identified. Experimental results concerning thermoelastic effects are in close agreement with theoretical estimates. Dissipation depends on the loading frequency and stress amplitude applied to the fatigue specimen. However, as the marked decrease in dissipation observed when testing a block at high stress was not easily interpretable in terms of material effects, we questioned the homogeneous fatigue test assumption.