Research Team 1 – Multi-scale modeling and characterization of coupled problems

In general, we are interested in the mechanical characterization of materials, mainly by indentation, with a materials approach taking into account various parameters (multiphasic, heterogeneous, porous, coated ...) and an approach rather oriented towards the development of the technique of indentation. All measurement scales are covered, from nano to macro, different modes are used (classic, CSM and multi-cyclic) and different properties are studied. In addition to the mechanical characterization of materials, we are interested in the development of instrumented indentation at different measurement scales for the determination of mechanical surface properties. It is mainly a question of hardness but also of the modulus of elasticity, the toughness and the mechanical properties of traction by inverse methods, the laws of behavior in creep and in relaxation. Our goal is to deepen our knowledge of the methodology, its contours and its limits for obtaining reliable and relevant properties. This is why we are studying a wide variety of materials in massive forms with different mechanical behaviors (from metals to ceramics), highly heterogeneous materials such as geomaterials (concretes), materials coated with thin films (<10 μm) or thicker (some 100 μm), homogeneous or heterogeneous structures or materials with a gradient of surface properties obtained by mechanical or thermochemical treatments. This diversity of case studies has allowed us to make good progress on the knowledge of new materials. However, there are still scientific barrier to be overcome, such as the taking into account of experimental parameters (rigidity of the machine, tip defect ...), the effect of size in indentation, the modeling of the mechanical properties of coated or gradient materials and finally the search for relevant parameters to characterize highly heterogeneous materials such as those of civil engineering.