Browse Publications Technical Papers 2001-01-1058

Simultaneous Topology and Performance Redesign by Large Admissible Perturbations for Automotive Structural Design 2001-01-1058

A methodology for topology and performance redesign of complex structures by LargE Admissible Perturbations (LEAP) has been developed since 1983 in the Department of Naval Architecture and Marine Engineering, the University of Michigan. LEAP theory has successfully solved various redesign problems for performance and simultaneous topological and performance changes. The redesign problem is defined as a two-state problem that consists of two structural states, States S1 and S2. State S1 has undesirable characteristics or performance which does not satisfy designer specifications. The unknown State S2 has the desired structural response and/or performance. The relation between State S1 and State S2 is highly nonlinear with respect to its response or topology. So far, LEAP algorithms have solved various redesign problems for large structural changes (on the order of 100%–500%) of State S1 with only one finite element analysis. The algorithm also successfully solved simultaneous structural response and topological changes with only 3–5 intermediate finite element analyses.
In this work, LEAP theory is extended to solve topology and performance redesign problems pertinent to automotive body structures. Shell quadrilateral elements are used for automotive applications with plate thickness as redesign variable. The designer specifications are imposed as constraints on modal dynamic and/or static displacement. A minimum change optimality criterion is used as in previous redesign problems. Topological changes give the designer guidelines on required structural stiffening. For metal sheet structures, the stiffened areas can be beads or any other type of sheet metal reinforcement. The results are a stronger structure that possesses the desired performance or characteristics and at the same time conforms to design space or geometric requirements.


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