Multi-step buckling optimization analysis of stiffened and unstiffened polymer matrix composite shells: A new experimentally validated method

A new multi-step optimization method is developed to predict the optimal fiber orientation in glass fiber reinforced polymer (GFRP) composite shells. The method contains 1) a regenerated genetic algorithm (GA) optimization strategy coupled with, 2) an analytical approach regarding assessing the failure of the tubular structure. Two critical factors, namely “ultimate buckling load” and “weight of structure” are particularly taken into account, while other crucial limitations, including angle and number of layers, shell thickness, and size of stiffeners, are considered in this study. Some experiments are conducted to evaluate the critical buckling pressure in GFRP specimens, and the obtained analytical results are verified through comparison with experimental ones. The results suggest that the application of this novel optimization algorithm leads to a decrease of 21% and 28% in optimum local mass of stiffened unsymmetrical angle-ply and unstiffened symmetrical angle-ply laminated composite shells, respectively.