Damage modelling at the mesoscopic scale for 4D carbon-carbon composites

Damage mechanisms and inelastic mechanical phenomena are modeled to the macroscopic scale for multiaxial loading. The studied material made. by S.E.P. (Societe Europeenne de Propulsion) is a 4D Carbon-Carbon composite comprising therefore four reinforcement directions. A very simple mathematical material model has been first derived for multiaxial loading as a consequence of some remarkable experimentally observed properties and the material geometry. The anisotropic continuum damage theory introduce by Ladeveze is used. To identify the material constants and functions characterizing the studied 4D CIC 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 done introducing a mesomodelling of the composite specimen, the meso-constituent being the fiber yarns, the matrix blocks and the interfaces. Finally, the identified material model has been checked on various experiments.