A methodology for optimally designing fibre-reinforced laminated structures with design variable tolerances for maximum buckling strength

Abstract

A procedure to design symmetrically laminated structures for maximum buckling load with manufacturing uncertainty in the ply angle—which is the design variable, is described. It is assumed that the probability of any tolerance value occurring within the tolerance band, compared with any other, is equal, and thus the technique is aimed at designing for the worst-case scenario. The finite element method is implemented and used to determine the fitness of each design candidate, and so the effects of bending–twisting coupling are accounted for. The methodology is flexible enough to allow any appropriate finite element formulation and search algorithm to be substituted. Three different tolerance scenarios are used for the purposes of illustrating the methodology, and plates with varying aspect and loading ratios, as well as differing boundary conditions, are chosen to demonstrate the technique, and optimally designed and compared.