Probabilistic-statistical approach to matrix damage and stress-strain behavior of 2-D woven SiC/SiC ceramic matrix composites

The matrix damage evolution in a 2-D SiC/SiC composite reinforced with fabrics of fiber bundles was predicted from properties of basic constituents using a finite element analysis of failure probabilities. Failure probabilities were computed using a finite element post processor including the multiaxial elemental strength model for handling fracture statistics under multiaxial stress-states. The associated stress-strain behavior of the selected elementary cell was derived from the stress analysis. The predicted matrix damage evolution was found in good agreement with that identified by microscopy on practical 2-D SiC/SiC woven composites under tension. The predicted stress-strain behavior and Young's moduli compared satisfactorily with the experimental data. The approach was then applied to a cell of fully dense 2-D woven SiC/SiC composite under tension, and then to a cell of conventional 2-D woven SiC/SiC composite subject to a gradient of forces. (C) 1998 Elsevier Science Limited. All rights reserved.