Two-Level Optimization of Dimensions and Stacking Sequences for Hat-Stiffened Composite Panel

Abstract

This paper describes both the development of a new low-cost optimization method for the optimal design of laminated composite structures, and a result of applying this method to the minimum weight design of a hat-stiffened composite panel subject to a buckling constraint. The new method is based on two levels of optimization. In the low level optimization, the fractal branch and bound method is used for a stacking sequence optimization. In the high level optimization, the particle swarm optimization technique is used for optimizing configurations of the hat-stiffened panel. Moreover, a Kriging-based response surface is used to find the global optimum, and not just to approximate an objective function value. For this purpose, we use the ‘expected improvement’ (EI) criterion defined in the Kriging model. The validity of the proposed method is examined and the results show that the method provides valuable solutions with good precision and a low computational cost.