Mechanical effects of oxidation induced shrinkage on organic matrix composites

International audienceThe present work is focused on investigating the effects, due to the shrinkage, on the mechanical states occurring in composites structures made of organic matrix having been subjected to a thermal-oxidation process. The oxidation actually induces some matrix shrinkage which is reported to generate high local stresses. In the present work, effective mechanical properties of oxidized composite plies are determined according to Eshelby-Kröner self-consistent homogenization procedure, depending on the progress of the oxidation process. The results are compared to the corresponding properties estimated by the finite-element method. The macroscopic stresses undergone by each ply of the structure submitted to typical loads are deduced from the classical lamination theory and by the finite-element method, whereas the local stresses in both constituents are calculated for each ply of the structure, through an analytical stress concentration relation