Difficulties with Non-Homogeneous Failure Criteria Like Tsai-Wu for Composite Laminates

摘要

In designing composite laminates, minimization of a suitable failure criterion is sometimes selected as the objective function. However, for inhomogeneous criteria, e.g. the Tsai-Wu criterion, this objective function may be inappropriate when the ratio of the applied load to the critical load is not close to, or for some materials even larger than, unity. We suggest that the use of a safety factor for the objective function is more appropriate, and demonstrate numerically that the use of the failure index may reduce the safety factor to first-ply-failure.