Optimization of Postbuckling-Stiffened Composite Aerostructures

Experimental and numerical evidence has shown that the occurrence of secondary instabilities, or mode-jumping, can have a detrimental effect on the structural integrity of thin-skinned stiffened composite panels. The sudden release of energy has been shown to initiate skin-stiffener debonding, leading to catastrophic fracture. As a consequence, it is common practice to increase the skin thickness in vulnerable areas, leading to non-optimal, i.e., heavier, structures. In this chapter, an optimization framework is presented which couples nonlinear high-fidelity finite element modelling, which is capable of capturing mode-jumping and the evolution and propagation of damage, with a genetic algorithm for use in the design of efficient and robust postbuckling composite structures.