Damage and Nonlinear Stress-Strain Behavior of Orthogonal 3-D Fabric Reinforced Si-Ti-C-O Fiber/Si-Ti-C-O Ceramic Matrix Composites

摘要

The damage progression in orthogonal 3-D fabric reinforced Si-Ti-C-O fiber/Si-Ti-C-O ceramic matrix composites (NUSK-CMC) was studied. In -situ measurement of microcrack was conducted by replica observation during loading-unloading tensile test. Effects of microcracks in longitudinal and transverse bundles upon macroscopic inelastic stress-strain behavior were analyzed in detail. Using a simple mechanical model for three-dimensional composites, stress distribution of longitudinal bundles was evaluated from the stiffness change associated with an established theory for matrix crack effects in the transverse bundles. In longitudinal bundles, the nonlinear behavior were calculated from unidirectional mechanical model considering matrix crack, interface debond and fiber fracture, and the fiber-matrix interface parameters were determined from hysteresis measurements and matrix crack density in the bundles. Inelastic stress-strain behavior for this NUSK-CMC was simulated.