Optimum design of laminated composite foam-filled sandwich plates subjected to strength constraint

Optimum design of laminated composite sandwich plates with both continuous (core thickness) and discrete (layer group fiber angles and thicknesses) de sign variables subjected to strength constraint is studied via a two-level optimization technique. The strength of a sandwich plate is determined in a failure analysis using the Tsai-Wu failure criterion and the finite elemen t method which is formulated on the basis of the layerwise linear displacem ent theory. In the first level optimization of the design process, the disc rete design variables are temporarily treated as continuous variables and t he corresponding minimum weight of the sandwich plate is evaluated subject to the strength constraint using a constrained multi-start global optimizat ion method. In the second level optimization, the optimal solution obtained in the first level optimization is used in the branch and bound method for solving a discrete optimization problem to determine the optimal design pa rameters and the final weight of the plate. Failure test of laminated compo site foam-filled sandwich plates with different lamination arrangements are performed to validate the proposed optimal design method. A number of exam ples of the design of laminated composite foam-filled sandwich plates are g iven to demonstrate the feasibility and applications of the proposed method . (C) 1999 Elsevier Science Ltd. All rights reserved.