A STUDY OF THE INFLUENCE OF INTERFACIAL DAMAGE ON STRESS-CONCENTRATIONS IN UNIDIRECTIONAL COMPOSITES

This paper uses a modified shear-lag model taking account of the tensi le load of the matrix to study the stress concentrations in unidirecti onal composites containing interfacial damage between fibres and matri x, and discusses the influence of the interfacial shear strength and o f the matrix-to-fibre tensile stiffness ratio on both the stress conce ntrations and lengths of damaged regions at the interface. The compute d results show that the stress concentrations in intact fibres adjacen t to cut fibres and matrix elements can be effectively reduced by shea r yielding or debonding at the interface, and can be increased as the interfacial shear strength and the matrix-to-fibre stiffness ratio inc rease. The lengths of damaged regions at the interface are decreased a s the interfacial shear strength is increased, but increased as the ma trix-to-fibre stiffness ratio is increased. (C) 1997 Elsevier Science Limited.