Design Optimization of Multibody Systems by Sequential Approximation

Abstract. Design optimization of multibody systems is usually established by a direct coupling of multibody system analysis and mathematical programming algorithms. However, a direct coupling is hindered by the transient and computationally complex behavior of many multibody systems. In structural optimization often approximation concepts are used instead to interface numerical analy-sis and optimization. This paper shows that such an approach is valuable for the optimization of multibody systems as well. A design optimization tool has been developed for multibody systems that generates a sequence of approximate optimization problems. The approach is illustrated by three examples: an impact absorber, a slider-crank mechanism, and a stress-constrained four-bar mecha-nism. Furthermore, the consequences for an accurate and efficient accompanying design sensitivity analysis are discussed. Key words: design optimization, approximation concept, design sensitivity analysis, transient dy-namic behavior, mathematical programming