The Wing Structure of an F3J/F5J Competition Sailplane: Topological Optimisation with Simplex Method and Additive Manufacturing

This research concerns the optimization study of the wing of an ultralight competition sailplane, category F5J/F3J. Fundamental for this category is the characteristic of lightness associated with good wing stiffness (bending/torsional). All the elements composing the wing of the sailplane were modelled in 3D by using the Autodesk Inventor parametric solid modeler. They were assembled in the FEM environment and were suitably constrained and studied from a structural point of view. The structural characteristics of the wing and its components were analysed in detail after assigning the materials currently used and adopting appropriate materials to make the same with the Additive Manufacturing (AM) technic. A topological optimization, performed by using the Simplex Method (SIMP), was conducted on the internal structure of the wing in order to lighten the ribs with the same performance. The experimental investigations implemented in the laboratory allowed the ’Oralight’ material used for the wing surface coating to be characterized. It is an extremely thin and light material, whose elasticity and strength were accurately assessed in this study. The data obtained, considered along with the elasticity and the resistance values of the other materials constituting the wing structure, taken from the literature, were inserted into the finite element simulations with the aim of evaluating the torsional and bending stiffness of the wing. Finally, the rib was redesigned using a FDM material which makes construction particularly simple.