Optimum design of composite structures subjected to multiple displacement constraints

Abstract

The paper presents an effective method for achieving the optimum design of composite structures subjected to multiple displacement constraints. Based on the optimality criterion method and some approximate engineering assumptions, this paper introduces a simplified expression relating the design variables to Lagrange multipliers, which correspond to displacement constraints. Therefore, the optimal design variables are derived from a smaller number of unknown coefficients. Thus the computational efficiency is greatly enhanced. Furthermore, the multilevel optimization technique is adopted. The optimum design variables are obtained in system level optimization. For more detailed design the ply thicknesses of a composite plate are adjusted in component level optimization by using the maximum strain energy criterion. A cantilever composite beam, subjected to strength and multiple displacement constraints, is studied as the illustrative example. The computational results indicate the efficiency of the method.