A multicriteria objective function optimization scheme for laminated composites for use in multilevel structural optimization schemes

Abstract A multilevel optimization scheme for large laminated composite structures is proposed, and a suitable element/lower-level optimization scheme using a multicriteria objective function is developed. The objective function combines a weight function and a strain energy change function into a utility function which is minimized and in which the relative importance of each part is reflected by weighting coefficients. Minimizing the change in strain energy ensures load path continuity in the overall structure when switching between upper and lower levels of optimization, and so decouples the problems at the two levels. Continuous lamina thickness and ply-angle variation is used to minimize the objective function while satisfying strain, buckling, and gauge constraints. Numerical applications are given to illustrate the effect of the weighting coefficients in the objective function on the final result, and to demonstrate the algorithm's effectiveness as a pure weight minimization routine.

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