基于最终失效强度的层合板结构的鲁棒优化分析

采用有限元方法分析复合材料层合板结构的最终失效强度，并以此对结构进行优化和鲁棒优化分析。层合板结构同时承受面内和面外载荷，每个单层板考虑基体失效和纤维断裂两种失效模式。当某一单层失效后采用比率退化法计算结构新的刚度，然后重新进行结构分析，直到求得结构的最终失效强度。以纤维方向角和层合板厚度作为设计变量，最终失效强度为目标，对结构进行优化。在此基础上，考虑了层合板结构的鲁棒优化分析。

ROBUST DESIGN OF LAMINATED COMPOSITE PLATES BASED ON THE LAST-PLY FAILURE CRITERION

A last-ply failure (LPF) analysis method for laminated composite plates is incorporated in the finite element method, based on this, optimization and robust optimum problems are presented. The composite structure is analyzed considering both in-plane and out-of-plane loads. For a lamina, two major failure modes are considered: matrix failure and fiber breakage. When a lamina has failed, the laminate stiffness is modified to reflect the damage, and stresses in the structure are re-analyzed. This procedure is repeatedly performed until the whole structure fails and thus the ultimate strength is determined. A structural optimization problem is solved with the fiber orientation and the lamina thickness as the design variables and the LPF load as the objective. Finally, robust optimum design method for laminates is presented and discussed.