Failure Criterion for Two-Ply Plain-Weave CFRP Laminates

We present an experimentally-based failure criterion for symmetric two-ply plain-weave laminates of carbon-fiber reinforced plastic. The criterion is formulated in terms of six force and moment stress resultants and consists of a set of three inequalities, related to in-plane, bending, and combined in-plane and bending types of failure. All failure parameters in the criterion are measured directly from five sets of tests. The new criterion is validated against an extensive data set of failure test results that use novel sample configurations to impose different combinations of stress resultants. It is found that the proposed criterion is safe for all test conditions and yet avoids excessive conservatism.