Materials and microstructures

The unit set of themes of research « Laws of Behavior, Microstructure and Processes » associates researchers complementary competences in experimental characterization, theoretical modeling and digital simulation.

The research projects carried out by this unit relate to the rheological behavior of the complex fluids, the rubber band-inelastic behavior of metals, solid polymers and the study of the penetrability of the piles by vibration.

Key Words:
• Micromechanical Approaches (polymeric, metals)
• Behavior of materials into quasi-static/dynamic
• Plasticity, damage and effect of recycling on mechanical properties
• Formatted of materials
• Digital simulations/finite elements

The scientific objective for these projects is to develop phenomenologic laws of behavior or physics which accounts for the effects of a certain number of parameters such as the speed of request, the temperature, the microstructure and their evolutions.

These models are implemented thereafter in computer codes for the digital simulation of tests in laboratory or the full-scale tests.

The results of the digital simulation are confronted with the experimental results in order to gauge the models and to check their relevance.

Of fundamental nature, research of this unit relates to also the industrial applications such as the fields of working of metals, the placement of polymers and the design.

The developed models of behavior are also exploitable for the numerical modeling of the biomechanical systems. For the elastic behavior anelastic of materials, we are interested more particularly in the development of laws of mico-macro behavior in which the local behavior is described by physical approaches. Thus, the microstructure plays a paramount part for the formulation of the constitutive laws. These approaches describe the deformation or the damage by the mechanisms specific to material considered.

In the case of the polymers, the plastic deformations are described by the molecular approaches. In the case of metals, the approaches based on the movements of dislocations are considered to describe plasticity, work hardening and the damage.

In the field of the processes, work relates to the numerical installation of simulators of industrial processes which take into account the evolution of the microstructure. Typically for metals, these numerical tools must take account of the evolution of texture during the process.

The economic stake such studies is the reduction of the costs by optimizing the number the operations or the quantities of matter.

Of nature applied, research in this direction relates to the industrial applications such as working of metals, the placement of polymers. The major scientific objective of this activity is to optimize the industrial processes for a given material or to optimize material for a given process.

This objective is achieved through two phases :
• a first phase of validation of our simulators by comparing the experimental results with those obtained by numerical modeling
• a second phase of prediction and optimization by studying the influence of various parameters of manufacture or material on the digital simulations.

International Collaboration :
• University of Aveiro, Portugal
• Georgia Institute of Technology, Atlanta, GA, USA
• University of California at San Diego, CA, USA
• Pacific Northwest National Laboratory, WA, USA
• Centre de Recherche Public Henri Tudor, Luxembourg
• Center for Advanced Engineering Fibers & Films, Clemson University & MIT, Clemson, SC, USA