An approach for shape and topology optimization integrating CAD parameterization and evolutionary algorithms

Expanding the scope of an structural optimization to the configuration or topology level is a perspective to further exploit the potential of a structural concept. An approach for shape, topology and configuration optimization is presented in this paper. The concept is based on three main elements: a parametric geometry modeler (CAD), a multiobjective evolutionary algorithm, which is able to deal with discrete and continuous variables, and at last process parallelization and management. A full parametric CAD-tool provides the parameterization, sizing parameters (e.g. sheet thickness), shape parameters (e.g. cutout geometry), topology parameters (e.g. number and position of stringer) and configuration parameters (e.g. placement of components). Based on the CAD model an FEM-Model is automatically generated. A special interface for controlling CAD (Pro/E) by the optimizer is developed at the Institute of Lightweight Structures (LLB). For optimization an evolutionary algorithm (EA) is applied, which is especially adapted for multi-objective optimization. Furthermore it can handle continuous and discrete parameters simultaneously with especially adapted operators. In order to overcome the high computational costs of EAs, a LINUX based PC cluster has been applied to parallelize the evolutionary process. An integrated application management environment is set up that keeps a database of all design and configuration variables, controls the execution of the different tools and also handles the optimization process and results. Furthermore it provides the optimization algorithms and tools for result visualization. Apart from a test example of a clamped beam with cutouts, the approach is applied to an instrument panel of a satellite.