Mechanical Behavior of Dense Carbons – CoMéCa

The CoMéCA project aims at modeling the mechanical behavior of carbon-based thermal protection systems with aerospace and defense applications. These multi-scale materials are made of complex architectures of carbon fibers and matrices, which both derive from graphite, yet being heavily disordered. Modeling the thermomechanical behavior of such structures requires knowledge of the individual behavior of each constituent, in addition to their interactions, from the atomic scale (typically one nanometer) to the largest scale of the complex architecture (sub-millimeter to centimeter). Our consortium, composed of LCTS (CNRS, U. Bordeaux, Safran, CEA/DAM), ISM (U. Bordeaux, CNRS) and CEA/DAM, proposes to approach this problem through a combined experimental/theoretical investigation. The experimental part will aim at preparing samples of the individual matrices in a suitable form, for detailed characterization and mechanical testing, and to perform the characterizations and tests. The objective will be to produce a large database of structures with associated structural and mechanical properties. The theoretical part will make use of recently developed bottom-up strategies based on atomistic modeling in order to build mechanical models with the help of numerical materials derived from actual ones. The principle is an image-guided atomistic reconstruction that makes use of experimental data obtained on real materials. Comparison between experimental and simulation results will allow establishing the laws governing the mechanical behavior at the mesoscopic scale, a necessary step towards the bottom up prediction of the behavior of composite materials at the macroscopic scale. Hence, important steps will be achieved in understanding the relationships between non-linear, anisotropic mechanical behavior and structural and textural features, which will enable a better design and optimization of future generations of carbon-based composite materials.