CAD-integrated Parametric Design Cycle for Structural Membranes

The design cycle of membrane structures consists of three interactive and highly nonlinear disciplines.Formfinding is performed in order to find a geometry that allows the prestressed structure to carry loadsthrough tension only. Once a formfound geometry is set, structural analysis needs to assess the structure’ssafety and usability. The most challenging step is the cutting pattern generation, which aims at finding theplanar pieces which can be elevated to build spatial membrane structures with a minimum deviation fromthe desired shape and prestress state. Since membrane surfaces are typically double-curved, they cannotbe developed into planar geometries. An optimization approach is necessary to solve this problem. The Variation of Reference Strategy (VaReS) is an innovative optimization approach, which simulates theactual mounting process in a mechanically accurate way.Isogeometric B-Rep Analysis (IBRA) allows the designer to perform analyses on the original CADmodel without leaving the CAD environment. High quality is ensured for the geometry and the me-chanical approximation by using NURBS for both the geometry representation and the shape functions. Additionally, the topology information of multipatches can be transferred to the analysis in order toenrich the design space. Since the entire CAD model can be accessed, trimmed surfaces can thus beincluded in the analysis. Parametric models allow the designer to examine a large variety of geometricaland mechanical entities with one model.CAD-integrated parametric analysis with IBRA elements has a large potential as the design cycle of amembrane structure - form finding, structural analysis and cutting pattern generation - can seamlesslybe integrated into CAD systems. This contribution gives a brief overview of IBRA and its inheritedadvantages for the whole design cycle. A special focus is put on the advanced method of cutting patterngeneration with the Variation of Reference Strategy and IBRA elements.     «

The design cycle of membrane structures consists of three interactive and highly nonlinear disciplines.Formfinding is performed in order to find a geometry that allows the prestressed structure to carry loadsthrough tension only. Once a formfound geometry is set, structural analysis needs to assess the structure’ssafety and usability. The most challenging step is the cutting pattern generation, which aims at finding theplanar pieces which can be elevated to build spatial membrane structures with...     »