DELAMINATION IN CROSS-PLY LAMINATED COMPOSITE SUBJECTED TO LOW-VELOCITY IMPACT

Delamination due to low-velocity impact of simply supported graphite/epoxy cross-ply laminate beams and plates was investigated. Both quasistatic and low-velocity impact testing were carried out in this study. For each loading condition, finite element analysis and experiments were performed to study damage growth and distributions. The mode II energy release rate for dynamic crack arrest G(IIa) was 75% less than the onset of crack propagation G(IIC). A quasistatic three-dimensional finite element analysis coupled with a G(II) greater-than-or-equal-to G(IIC) criterion was used for the onset of delamination propagation, and G(II) less-than-or-equal-to G(IIa) criterion was used to arrest the propagating crack and to estimate the delamination area. Delamination area determined by this method correlated well with the test results.