MINIMUM WEIGHT DESIGN OF SYMMETRICAL ANGLE-PLY LAMINATES UNDER MULTIPLE UNCERTAIN LOADS

An angle-ply laminated plate is optimized with the objective of minimi zing the weight of the plate taking into account uncertainties in the multiple transverse loads. The weight is proportional to the laminate thickness which is minimized subject to deflection and buckling constr aints under the least favourable loading with the ply angles taken as design variables. The convex modelling approach is employed to analyse the uncertain loading with the uncertain quantities allowed to vary a rbitrarily around their average values subject to the requirements tha t these variations are bounded in L(2) norm and represented by a finit e number of eigenmodes. The effect of uncertainty on the optimal desig n is investigated quantitatively. It is shown that the minimum weight increases with increasing level of uncertainty and the optimal ply ang les also depend on the level of uncertainty.