Quadratic Stress Criterion for Initiation of Delamination

摘要: The initiation ofdelamination in graphite/epoxy specimens was investigated both analyt ically and experimentally. Three specific laminate families were investigated: [±15n]s, [± 15 n /0n]s, [0n / ± 15n] s with the normalized effective ply thickness, n, varying from one to five. Delamination determined have occurred when a drop load detected delamination observed on replication of specimen edge. Measured stresses correlated using strain energy release rate approach Quadratic Criterion introduced herein. unable accurately correlate data for two three fami lies. clearly shows that critical value is dependent thickness. Criterion, an average stress criterion which compares calculated out-of-plane interlaminar their related strength param eters, proposed excel...