Progressive damage and delamination in plain weave S-2 glass/SC-15 composites under quasi-static punch-shear loading

Quasi-static punch-shear tests are carried out on plain weave (PW) S-2 glass/SC-15 epoxy composite laminates with a right circular cylinder punch. Load-unload tests are performed to identify the sequence and extent of damage and the corresponding displacements at which they occur for a wide range of laminate thicknesses. Energies absorbed at different levels of damage are obtained from the load-unload curves. Two different support spans of 25.4 min (1 in.) and 101.6 min (4 in.) diameter with different layers (1, 2, 4, 6, 11, and 22 with 0.6 mm ply thickness) of composite laminates are tested under quasi-static loading to identify compression-shear and tension-shear dominated modes of damage. After each test, the damaged plates are sectioned to visualize the extent of delamination and material damage. Numerical punch-shear experiments are conducted using LS-DYNA 970. The numerical modeling is carried out using a newly developed composite damage model, namely MAT 162, which has been incorporated into LS-DYNA. MAT 162 uses damage mechanics principle for progressive damage and material degradation. Input data required in MAT 162 have been calibrated to match the experimental results of 22-layer composite plate of both spans (25.4 and 101.6 mm). The calibrated material properties have been used to simulate other thicknesses, and the simulated results show good agreement with experiment results. It has been found that the dominant damage mechanisms are delamination and fiber breakage due to shear and tension. (c) 2005 Elsevier Ltd. All rights reserved.