NOTCHED STRENGTH AND FRACTURE CRITERION IN FABRIC COMPOSITE PLATES CONTAINING A CIRCULAR HOLE

The effects of the hole size and the specimen width on the fracture behavior of several woven fabric composite plates are experimentally investigated in tension. It is shown in this paper that the characteristic length (d(o)) in the Point Stress Criterion (PSC) depends on the hole size and the specimen width. A modified PSC for predicting the notched strength is proposed. An excellent agreement is found between the experimental results and the analytical predictions using the modified PSC. When the unstable fracture occurred, the equivalent critical crack length (a(c)) corresponding to the damage zone size is about twice the characteristic length. The characteristic length decreases with an increase in the notched strength. The critical energy release rate (G(c)) corresponding to the unstable fracture criterion is independent of the hole size for the same specimen width. G(c) increases with an increase in the specimen width. These results can be explained by the correlation between the G(c) and the notch sensitivity factor (k).