Staff scientist, Materials Sciences Corporation, Bethlehem Pike, Spring House, PA
Pages: 17 Published: Jan 1990
Application of fracture mechanics to through cracks in thin laminated composite plates does not yield good correlation with test data because of large zones of surface damage near the crack tips. However, for thick laminates with through or surface cracks of moderate sizes (of the order of several ply thicknesses), influence of damage zones is usually small and stress analyses based on homogenization assumption and fracture mechanics approach should yield reliable estimates of failure loads. In this paper, stress-intensity factors for elliptic cracks in transversely isotropic (in planes perpendicular to the cracks) and ortho-tropic media obtained from numerical solutions are reported. In addition, appropriate correction factors to obtain stress-intensity factors for surface cracks of semielliptic shapes are estimated using a limited number of finite-element results. Test data available in literature are correlated with analytical predictions for failure of critical ligaments. Other relevant failure mechanisms are also discussed.
composite laminates, surface cracks, surface cuts, fracture mechanics, elliptic cracks, semielliptic cracks, homogenization, surface damage
Paper ID: STP23434S