An optimization procedure using a genetic algorithm (GA) is proposed to determine the optimal stacking sequence of laminated composite plates for the maximum buckling load under several different loadings, such as uniaxial compression, shear, biaxial compression, and the combination of shear and biaxial loadings. A series of optimal design is conducted for composite laminates having different aspect ratios, load conditions, and number of plies. Critical buckling load is taken as fitness function and fibre orientations are taken as design variables. A performance index is introduced to represent the effectiveness of optimal design with respect to worst case design. Then, for uniaxial compression loading, postbuckling behaviour is analysed numerically for the optimally designed composite plates as well as the worst case design composite plate. It shows the outstanding postbuckling performance of one of the optimally designed composite plates against the worst case design composite plate. Also, a GA finds the global solution without requiring auxiliary information such as derivatives of the objective function.
