Interactive growth of multiple fiber-bridged matrix cracks in unidirectional composites

The equivalence between monotonic and cyclic loading for multiple cracking is the same as that for a single crack in the matrix of a fiber-reinforced composite having multiple cracks. The interactions among cracks and slip zones reduce the crack tip stress intensity factor in multiple cracking. The growth of the fatigue crack is slower than that for a single bridged crack or for multiple nonbridged cracks. This significantly delays the onset of steady-state crack growth.