Topology Optimisation of Thin Membranes Applied on a Parafoil Rib

Membrane structures have a wide field of application in modern engineering due to their low weight-to-area ratio, which is especially exploited in kite design. The internal pressure of ram-air kites has to be well distributed over all cells in order to maintain the aerodynamic shape. By cutting holes in each rib the stagnated air can provide the required pressure in each cell. The question is, where to cut the holes such that the structural performance does not cause a decrease in aerodynamic performance? For that reason the membrane finite element (FE) solver developed in TU Delft in combination with geometrically non-linear topology optimization was utilized. The membrane FE solver is based on the tension field theory which allows the use of low density meshes and still being able to determine the membrane states: taut, wrinkled, or slack. Topology optimization supplies the user with an optimum material distribution in a design space for a given load. The combination of membrane FE solver and topology optimization resulted in an efficient method, which successfully reduced slack and wrinkled areas in membranes. The rib structure was optimized in a combination of two flight conditions, and the results indicate hole positions similar to the real ram-air rib model.European Wind Energy Master (EWEM)Aerospace Structures and Computational MechanicsAerospace Engineerin