Transition from Brittle to Quasi-Brittle Behavior in Fiber Reinforced Brittle Matrix Composites

摘要

The transition from brittle to quasi-brittle behavior was studies as a funtion of fiber volume fraction and crack length in fiber reinforced ceramic matrix composites. A failure mechanism transition from catastrophic to non-catastrophic failure, coupled with the transition from flaw-sensitive to flaw tolerant behavior, was observed by varying the preexisting flaw size and the fiber volume fraction. These transitions were explained by analyzing the relations between ultimate strength, matrix-cracking stress, fiber volume fraction, and preexisting flaw size of the composite materials. The conditions to ensure quasi-brittle behavior for both fiber reinforced ceramic and fiber reinforced cementitious composites were discussed.