Optimization of a parametric composite wing using engineering sketch pad and NASTRAN

Metallic aircraft wings are usually not optimized to their fullest potential due to shortage of development time. This problem gets compounded when it comes to optimization of composite wings. With roughly $1000 worth of potential fuel savings per pound of weight reduction over the operational life of an aircraft, airlines are trying to minimize the weight of aircraft structures. In this study, a multi-level optimization strategy to optimize the weight of a composite transport aircraft wing is proposed. The loads on the wing are applied from a stick model as is done in the industry. A parametric software called Engineering Sketch Pad (ESP) is used for the geometry creation and Nastran is used to optimize the model. The part is assumed to initially have some arbitrary number of composite super plies. Super plies are a concept consisting of a set of plies all arranged in the same direction. The thickness and orientation angles of the super plies are optimized. Then, each ply undergoes topometry optimization to obtain the areas of each super ply taking the least load so that it could be cut and removed. Each of the super plies are then optimized for the thickness and orientation angles of the sub plies. The work presented on this paper is part of a project done for Air Force Research Laboratory (AFRL) connecting the parametric geometry modeler (ESP) with the finite element solver (Nastran).