Steady-State and Multiple Cracking of Short Random Fiber Composites

摘要

This paper analyzes the pseudostrain-hardening phenomenon of brittle matrixcomposites reinforced with discontinuous flexible and randomly distributed fibers, based on a cohesive crack-mechanics approach. The first crack strength and strain are derived in terms of fiber, matrix, and interface micromechanical properties. Conditions for steady-state cracking and multiple cracking are found to depend on two nondimensionalized parameters. The results are therefore quite general and applicable to a variety of composite-material systems. Phrased in terms of a failure-mechanism map, various uniaxial load-deformation behaviors for discontinuous fiber composites can be predicted. The influence of a snubbing effect due to local fiber/matrix interaction for randomly oriented crack-bridging fibers on the composite properties is also studied. (MM).