Assessment of Impact Damage in Composite Structures

In order to provide through-life support for structural components fabricated from advanced composite materials, it is desirable to establish a damage tolerance methodology. There are many difficulties in meeting this objective, including the multiplicity of failure modes, the numerous types of potentially significant defects which may arise during manufacture or in service, and the sensitivity to moisture and temperature. This paper focuses on the problem of impact damage and reviews research undertaken at ARL in recent years related to the analysis and testing of impact damage composite laminates. It is shown that the residual strength of impact damaged laminates reduces to an asymptotic limit as the size of the damage increases and that uniaxial S-N curves for damaged laminates have a generic shape with a pronounced threshold (endurance) level. Composite materials, Impact damage, Laminates, Bonded composite repairs, Damage tolerance, Aeronautical research.