Integrated structural modelling, adaptive analysis and shape optimization

• Main Author: Sienz, J.
• Published: Swansea University 1994
• Subjects: 502.85
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639033

The present work is concerned with the development of procedures for an integrated system for computer aided structural optimization including topology optimization, image processing and shape optimization for two dimensional structures. At the beginning, such a system is introduced. This system integrates aspects of design and analysis modelling, behaviour sensitivity analysis, optimization and creative control via interactive graphics. A satisfactory solution of structural optimization problems can only be achieved by having a profound knowledge of each of these aspects. The introduction of an integrated system for structural optimization is followed by the establishment of a pool of <i>blocks</i> to build such a system. Firstly, a flexible shape definition tool for two dimensional structures using <i>B</i>-splines is shown. This is followed by an adaptive, automatic mesh generator for unstructured meshes consisting of triangular or quadrilateral meshes which allows to generate full FE problem definitions. The FE analysis is carried out using this input for plane stress/plane strain problems, solids of revolution and for engineering problems governed by the Helmholtz equations. The accuracy of the FE analysis is improved by applying adaptive refinement methods in combination with the Zienkiewicz-Zhu error estimator and nodal averaging or the SPR method to compute nodal stresses. For shape optimization, the behaviour sensitivities of the structure are computed using semi-analytical methods (<i>exact</i> or conventional) or the global finite difference method. The optimization is carried out using mathematical programs which are used as <i>black boxes</i>. These tools are then combined to build two applications for integrated structural optimization.