Reliability-based robust of symmetric laminated plates subject to last-ply failure

This paper proposes a procedure to the robust design of composite laminates with initial imperfection under probabilistic considerations. A probability progressive failure mode of composite laminates is adopted to evaluate the structural reliability. The initial imperfection, strength parameters are considered as random variables, matrix cracking and fiber breaking are defined as the two basic failure modes. Ply-level failure probability is evaluated by the first order reliability method (FORM) and system reliability is computed based on the significant failure sequences. A structural optimization problem is solved with the fiber orientation and the lamina thickness as the design variables, the maximization of the system reliability index as the objective. Finally, robust design method for laminates is presented and discussed.