Design and optimisation of composite corrugated skin for a span morphing wing

The concept of span morphing aircraft is attracting a lot of attention due to the demands to enhance flight performance and control authority. Corrugated laminates provide a good solution for the skin of a span morphing wing due to their extremely anisotropic behaviour. Although corrugated skins have been proposed for camber morphing, they have not been proposed for span morphing. Hence the main focus of this paper is to optimise the geometry of the corrugated skin to minimize the axial stiffness, with constraints of material strength limits and out-of-plane deformations due to the aerodynamics. Two aerodyanic solvers, Tornado Vortex Lattice Method (VLM) and XFOIL, are compared and a Genetic Algorithm (GA) is used as the optimizer. Parametric modeling and calculation by ANSYS APDL was used to generate the finite element model and perform the analysis automatically based on the global and local geometric parameters. The parameter sensitivity is also analyzed and discussed. The optimization results show that XFOIL is more accurate than VLM for this analysis. The maximum displacement constraint causes the optimizer to choose fewer corrugations rather than increase the sheet thickness. This implies that the thickness has a higher impact than the number of corrugations on the axial stiffness. The optimization results show that the corrugation height and angle are maximized as they seem to have less influence on the maximum out-of-plane displacement.