An analytical sensitivity theory-based optimization method for composite structures with large-scale variables

Abstract

This research focusses on large-scale variable optimization techniques for commercial composite wing structures. To achieve a more complete set of results, the layer thickness for composite layers with the same material and ply direction, are set as a design variable in this study. An analytical approach was utilized to deal with the sensitivity analysis so as to study the relationship between displacement, stress and strain constraints. In order to improve the applicability and user-friendliness, the procedure of sensitivity analysis has been programmed within Fortran and integrated into a Computer-Aided Engineering (CAE) software named HAJIF. To compare the consistency and efficiency, the analytical sensitivity calculation method, along with the finite difference method and a semi-analytical method, were employed to optimise a composite aircraft wing structure. The analytical method was found to have the best consistency and efficiency amongst the three optimization methods. With the aid of HAJIF, the wing was optimized with a weight loss ratio of 8.9%. The total optimization time was is 56 times quicker than the finite difference method and semi-analytical method.