Topology Optimisation of Thin Membranes Applied on Parafoil Rib Structure

Membrane structures have a wide field of application in modern engineering. It ranges from aerospace to civil engineering, and even in bioengineering to analyse cell structures. The advantage of membranes is their low weight-to-area ratio which is especially exploited for kites. In this thesis the rib structure’s topology of a parafoil ram-air kite was optimised. Ram-air kites are used for paragliding but also in airborne wind energy, a wind energy design concept to harvest wind with kites and aircraft. To ensure a good relation between weight, deformation, and hole size in the rib, topology optimisation in combination with a geometrically non-linear finite element solver was applied. The membrane topology optimisation was based on complementary energy minimisation, which proved to result in a stable optimisation scheme which successfully reduced the density in slack and wrinkled element regions. The Solid Isotropic Material with Penal-isation (SIMP) method from (Bendsøe, 1989) was adopted for the optimisation which uses a fictitious density variable for each finite element, changing its Young’s modulu