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 an d mode ratio for a locally buckled, compression loaded laminate which contains either a single delamination or two symmetrically located del aminations. 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 pe rcentage of crack-tip shearing mode at a given displacement, are highe r in the configuration which contains two delaminations.