A Multi-Stage Algorithm for the FEM Design of Composite Sandwich Panels Subjected to Multiple Manufacturing Rules

This paper proposes a method to design optimal composite sandwich panels subjected to multiple blending rules and external forces. The method uses a two-step algorithm. The first step seeks to obtain the optimal stacking sequence for a laminate, using a blind A* searching scheme over an incremental decision tree. This A* search provides the non-local minimum solution (looking for the best ply orientations and the best core thickness) using a minimum number of finite element method (FEM) evaluations. Once the stacking sequence for the lightest constant-thickness laminate is determined, the second step is to perform a peeling-off process using a simulated annealing algorithm. The final result is an even lighter laminate with a variable thickness distribution. This algorithm is intrinsically discrete and, unlike most gradient-based techniques, is not affected by local minima. It is important to note that the optimization process is enhanced by manufacturing constraints (blending rules), which are fulfilled whenever a feasible solution exists. The algorithm could therefore be a suitable choice for topology purposes whenever the laminate is subjected to a set of blending rules and no constraint violation is allowed.