Résumé
Optical techniques associated with quantitative imaging methods have been developed considerably over the last twenty years. During a deformation process, these techniques enable us to obtain discrete field measurements, invaluable not only to characterize and identify material behaviors but also for better distinguishing "material" effects from "structure" effects at an observation scale imposed by the optical systems. For example, digital image correlation (DIC) gives access to kinematical data and allows considering the homogeneous character of deformation fields; infrared thermography provides temperature fields and gives information about the dissipative nature of deformation mechanisms (viscosity, plasticity, damage, etc.). It also enables us to show the existence of heat coupling sources which translate a strong interaction between thermal and mechanical states (thermodilatability, first order phase change, rubber effects, etc.).