Effect of Fiber Fracture and Matrix Yielding on Load Sharing in Continuous Fiber Metal Matrix Composites

This paper addresses the issue of stress redistribution in the presence of a fiber fracture in a composite lamina. Stress elevation in the fiber adjacent to the broken fiber is the focus of this study. The stress concentration effects in the vicinity of the fiber break and its influence on the neighboring intact fiber is analyzed using the finite element method as a function of fiber volume fraction. The role of the inelastic behavior of the matrix in causing the stress elevation is studied. It is found that the state of stress in the intact fiber is affected significantly by the propagation of the plastic front due to matrix yielding. The local stress field is affected also if the fiber break is followed by interfacial debonding. Titanium matrix reinforced with continuous fibers of silicon carbide is chosen as the metal matrix composite system for this study. Experimental comparisons are made with tension tests conducted using a single-ply lamina.