Debond modeling for multidirectional composites Original Research Article

Damage mechanisms and inelastic mechanical phenomena are modeled at the macroscopic scale for multiaxial loading. The studied material made by SEP (Société Européenne de Propulsion) is a 4D Carbon–Carbon composite comprised of four reinforcement directions. A very simple mathematical material model has been derived first for multiaxial loading as a consequence of some remarkable experimentally observed properties and the material geometry. The anisotropic continuum damage theory introduced by Ladevèze is used. Identifying the material constants and functions characterizing the studied 4D C/C material is a rather difficult task: fiber debonding near the edges is very important for tensile tests. To go further in the test analysis, large finite element computations have been performed and presented in this paper introducing a meso-model of the composite specimen, the meso-constituents being the fiber yarns, the matrix blocks and the interfaces. Finally, the identified material model has been verified through various experiments.