A micromechanical model for damage progression in woven composite systems

Damage progression in woven composites is modeled for multiscale analysis of structures. The proposed model is a representative volume element (RVE) of the woven material, derived from micrographs. In principle, it is applicable to any woven system with periodic fiber placement; however, the focus in this paper is on 3D weaves. The domain and boundary conditions of the RVE are selected such that the model can serve as a repository for predicting the overall behavior under general, multiaxial stress states. The overall response due to applied stress, or strain, and local damage is evaluated by a transformation field analysis (TFA) scheme. Damage mechanisms observed under quasi-static and impact loads are implemented. This includes matrix cracking, frictional sliding and debonding of the fiber bundles, and fiber rupture. The local stress components affected by the active damage modes are removed or reduced by superimposing a transformation stress field on the elastic field caused by the overall loads in the undamaged material. This results in a local stress field that is within the affordable local strength magnitudes, and an overall transformation stress, which modifies the elastic estimate. Implementation of the material model in quasi-static and dynamic finite element procedures is discussed, and examples, which illustrate the model capabilities, are presented. (C) 2003 Elsevier Ltd. All rights reserved.