Refined preliminary weight estimation method for multidisciplinary shape optimization of lifting surfaces

An advance structural sizing method for wing structural weight estimation is developed. The method is based on the elementary, physics based, analyses of the simplified structure to determine the amount of required material to resist the applied loads. In this new weight estimation method, the effect of wing outer (aerodynamic) shape on the wingbox structural weight is taken into account. A mathematical equation is derived, which relates the wingbox structural weight to the wing outer shape. The weight estimation method is validated for several existing passenger aircraft. Using this new weight estimation method, the wing shape can be optimized not only for the best aerodynamic properties, but also for the minimum structural weight. A series of optimizations is performed to optimize the wing shape for a general objective function, which includes both aerodynamic and structural properties of the wing. Minimizing of the aircraft maximum take-off weight is used as the objective function. Different structures are tested including metal and composite ones. The latter includes different composite layups. The results of the optimizations show that the optimum wing shape depends on the structural concept used for different internal structures