The pressurised air in pneumatic membrane structures takes part at the load bearing. In combination with a 0.25mm thick ETFE foil these are one of the lightest possible kinds of structures. The large deformations and the thin polymer foil require a geometrically and physically nonlinear static analysis. In this work the mass of the structure is considered to stay constant during the process of deformation. Hence the pressurised air in the structure is coupled to the volume and changes its magnitude when the volume changes. With that for example air inflated structures subject to short term acting loads such as wind can be simulated even if the structure is connected to a pump. Because often the reaction time is out of economic reasons relatively slow and the diameter of the tube leading to the structure is small to fulfil aesthetic requirements. The above described phenomenon is herein called pressure volume coupling and considered analytically in the structural analysis. If the volume changes, the enclosed pressure and it’s thereof resulting change in magnitude is applied as follower load to the membrane structure and a geometrically nonlinear analysis is performed. Therefore a nonlinear algorithm in the finite element code Carat++ is enhanced to simulate pneumatic membrane structures. Carat++ is the research code at the Chair of Structural Analysis, Prof. Dr.-Ing. K.-U. Bletzinger, TU Munich. To validate the results rectangular pneumatic structures in the shape of a cushion made of ETFE foil are experimentally investigated in cooperation with the Institute of Photogrammetry and Cartography, TU Munich [Can11] and Seele Cover. Stress optimised patternings and cutting patterns consisting of multiple sheets are compared. For the simulation imperfections are considered to model realistic conditions and to compensate manufacturing inaccuracies. The nonlinear behaviour of the ETFE foils is approximated by the multi linear elastic isotropic material law. This was validated with blow up experiments of a circular ETFE membrane at the Chair of Structural Design, Prof. Dr.-Ing. R. Barthel, TU Munich [Sch09]. The thesis is based on the research of the Chair of Structural Analysis, Prof. Dr.-Ing. K.-U. Bletzinger [Jru09], [AdOC12], [Lin09], [Die09] and DFG BL 306/12 ""Material Appropriate Numerical Methods for Simulation, Formfinding and Patterning of Membrane Structures made of Polymer Foils"" part ""Extended Simulation Methods for Pneumatic Structures and their Experimental Validation"".     «

The pressurised air in pneumatic membrane structures takes part at the load bearing. In combination with a 0.25mm thick ETFE foil these are one of the lightest possible kinds of structures. The large deformations and the thin polymer foil require a geometrically and physically nonlinear static analysis. In this work the mass of the structure is considered to stay constant during the process of deformation. Hence the pressurised air in the structure is coupled to the volume and changes its magnit...     »