Failure of delaminated interply hybrid composite plates under compression

The purpose of this work is to study the buckling loads, delamination growth loads, and failures of delaminated interply hybrid composite plates under compression. Non-linear buckling and post-buckling analyses are conducted to predict the delamination buckling load and delamination growth load. In order to predict the delamination growth load, the total strain-energy release rate criterion, criterion of strain-energy release rate component, and interlaminar-stress criterion are used. Experimental results are also provided to compare with the prediction. The results indicate that non-linear buckling analysis has values very close to the buckling loads from the experiments and the agreement with the delamination growth loads is reasonable. For global buckling mode, the buckling loads are suggested to represent the failure loads of delaminated composites. For mixed and local buckling modes, the failure of the delaminated composite is attributed to the growth of delamination. An increase in the number of glass-fiber layers within an interply hybrid composite results in a decrease in the buckling load and the delamination failure load. A local symmetry stacking sequence has a lower buckling load and delamination failure load than an approximately globally symmetric stacking sequence.