Investigation of Successive Failure Modes in Graphite/Epoxy Laminated Composite Beams

The determination of failure modes in composite materials is often difficult to characterize because of the composition and variety of these materials. Several theoreti cal failure theories have been proposed, but no single one is accurate for every composite material; most of them predict only the first failure. Since most composites structures may still carry load after one or more plies have failed, the behavior of composite laminates is investigated beyond the first failure. This article presents a theoretical and experimental in vestigation of the successive failure modes of graphite epoxy laminated beams. Two failure theories are used: the maximum stress and the Tsai-Wu failure theories. Calculations are based on laminated plate theory.