A Comparison of Energy Release Rates for Locally Buckled Laminates Containing Symmetrically and Asymmetrically Located Delaminations

Results are presented from a study to determine energy release rate and mode ratio for a locally buckled, compression loaded laminate which contains either a single delamination or two symmetrically located delaminations. It is shown that, at a given applied load or displacement, significantly different values of energy release rate and mode ratio may exist in the two configurations. In general, the rate-of-increase of energy release rate with increasing displacement, as well as the percentage of crack-tip shearing mode at a given displacement, are higher in the configuration which contains two delaminations.