8 Pages

Optimum Buckling Design of Composite Stiffened Box Sections Using Finite Strip Approach and Genetic Algorithm Technique

WithH.R. Ovesy, H. Assaee

In this paper a genetic algorithm optimization technique has been implemented to find the optimum buckling performance of some composite stiffened boxes subjected to pure compression. The fitness function for the proposed algorithm is a semi-analytical approach called the finite strip method. The skin of the box is assumed to be manufactured of high strength Carbon-Epoxy pre-impregnated ply sheets, having symmetric cross-ply lay-up configuration (i.e. [(0/90)4]s). The stiffeners are made of the same material, but, with symmetric angle ply configuration (i.e.[(±θ)4]s). In this paper, the optimum fiber orientation angle of the stiffeners for the best buckling performance of the structure has been sought. Two groups of stiffeners (i.e. the blade stiffeners and the L-type stiffeners) are considered. The analysis of the results has revealed that the optimum fiber orientation of the stiffener with an angle-ply lay-up configuration strongly depends on the buckling mode shape of the box section as well as the type of the stiffener. Moreover, the proposed scheme is proved to be quite efficient in achieving the optimum configuration of the structure with minimum effort. As a result, the buckling performance of the structure could be significantly enhanced by the implementation of the current method.