MULTIOBJECTIVE OPTIMIZATION OF LAMINATED PLATES FOR MAXIMUM PREBUCKLING, BUCKLING AND POSTBUCKLING STRENGTH USING CONTINUOUS AND DISCRETE PLY ANGLES

The optimal design of uniaxially loaded laminated plates subject to el astic in-plane restraints along the unloaded edges are given for a max imum combination of prebuckling stiffness, postbuckling stiffness and buckling load. The results are also obtained for biaxially loaded plat es without elastic restraints. The method of solution involves definin g a design index comprising a weighted average of the objective functi ons and identifying candidate configurations which have to be optimize d and compared to determine the best stacking sequence. This multiobje ctive approach leads to improved prebuckling, buckling and postbucklin g performance. A similar approach is adopted in the case of discrete p ly angles with the provision that these angles can only take predefine d values. From a manufacturing viewpoint, using only certain fibre ori entations such as 0, +/-45 and 90 degrees is advantageous and cost-eff ective. The multiobjective design results are compared to single objec tive ones, and the effect of various problem parameters on the optimal designs are numerically studied. It is observed that the resulting tr ade-off among the different objectives are not severe leading to well- balanced laminates with regard to the range of loads they are required to carry. A comparison of continuous and discrete optimization indica tes that both designs lead to comparable load carrying capacity, with regard to different objectives. Copyright (C) 1996 Elsevier Science Lt d.