Mechanics of Materials has experienced this last decade a considerable expansion. The widening, to non strictly mechanic sciences, of available knowledge and data about the material behaviour has permitted to get a global view of the phenomena accompanying the deformation processes. The use of innovative experimental techniques, the writing of consistent theoretical framework and the recourse to high-performance numerical methods allow to analyse, to understand and to simulate the materials behaviour. Two research areas are particularly active these last years. On the one hand, the analysis of the microstructure of materials reveals the phenomena associated with the deformation process, and the use of scale transition techniques permits to integrate this description and to derive a more valuable macroscopic modelling. On the other hand, these phenomena often require variables that complete the classical displacements, strain or efforts of the mechanics. The taking into account of a temperature or a volumic fraction of phase in the constitutive equations implies the modelling of couplings between variables and the derivation of an adapted framework. The interest of this approach is again to get a more valuable description of the material behaviour, and also to use these additional variables as real tracers of the deformation process of the material