Integrated Design Approach for Shell Structures Using Isogeometric Analysis

Shell and tension surface structures are characterized by complex curved geometries with a potential for structural efficiency and formal quality. To unveil this potential, it is essential to define, modify and analyse complex geometries in an integral way. Describing complex, free-form geometries, within a computer-based design process, non-uniform rational B-Splines (NURBS)-based methods can be considered as standard within the common working process. The mathematical description of geometry with NURBS within a finite element-based analysis has become known as isogeometric analysis (IGA). As the basic descriptions of design and analysis models are equivalent, transforming steps (such as “meshing”, etc.) become irrelevant, and it is possible to fully unify the design and analysis environment. For the direct integration of isogeometric-based structural analysis into the design process the authors developed an interface for the computer aided design (CAD) environment that can directly access a broad field of analysis tasks (such as structural analysis, form-finding, etc.). As a result, the designing architect or engineer is capable of instantly estimating the structural qualities of arbitrary geometries. The integration of architectural and structural design by IGA with CAD enables an integrated design approach. This will be demonstrated in the context of the design of shell structures. To support the design process, the interface contains tools to provide important values such as strain energy to, for example, evaluate the structural efficiency of a random shell geometry within an early design stage. This strongly supports the designer to meet different design criteria derived from either structural or formal aspects. After a brief introduction of the isogeometric analysis method, this paper will highlight the potentials of this method through a variety of case studies. In each study both engineering and architectural design aspects will be addressed by comparing the process and the results of finite element analysis, and highlighting the integrated variability of design.