Aeroelastic optimization of an aerobatic aircraft wing structure

This paper aims at presenting an investigation into a minimum weight optimal design and aeroelastic tailoring of an aerobatic aircraft wing structure. Firstly, analytical and FE models were created for the original metallic wing and an improved composite wing box structures. In order to validate the numerical models, predicted vibration parameters of the metallic wing box were compared with the experimental results. Comparison was also made for the predicted stress results between the metallic and the composite wing box structures of different dimensions and laminate layups. Secondly, based on a minimum weight composite wing box model of adequate strength the investigation was focused on the aeroelastic tailoring of the wing box by employing the gradient-based deterministic optimization method. The study demonstrates that in addition to a significant weight saving, up to 30% increase of flutter speed for the composite wing box can be achieved by optimizing the fibre orientations of the wing skin and spar web laminates. The optimized laminates are trimmed and reinforced to meet the manufacture and strength requirements with little compromise of flutter speed and a minor weight penalty.