MATRIX CRACK SPACING IN BRITTLE MATRIX COMPOSITES

A model describing the evolution of matrix cracks in unidirectional continuous fiber, brittle matrix composites is developed. The approach involves calculation of the steady state strain energy release rate available for crack extension in terms of the constituent properties, the applied stress and the distances to the neighboring cracks. Interactions between cracks are found to occur when the crack spacing falls below twice the slip length. The model provides an analytical solution to the crack spacing for periodic arrays of cracks. Comparisons are conducted with predictions derived from computer simulations of random cracking. The effects of the matrix flaw density are briefly considered.