APPLICATION OF TOPOLOGICAL OPTIMIZATION TECHNIQUES TO STRUCTURAL CRASHWORTHINESS

The topological optimization of components to maximize crash energy ab sorption For a given volume is considered. The crash analysis is perfo rmed using a DYNA3D finite element analysis. The original solid elemen ts are replaced by ones with holes, the hole size being characterized by a so-called density (measure of the reduced volume). A homogenizati on method is used to find elastic moduli as a function of this density . Simpler approximations were developed to find plastic moduli and yie ld stress as functions of density. Optimality criteria were derived fr om an optimization statement using densities as the design variables. A resizing algorithm was constructed so that the optimality criteria a re approximately satisfied. A novel feature is the introduction of an objective function based on strain energies weighted at specified time s. Each different choice of weighting factors leads to a different str ucture, allowing a range of design possibilities to be explored. The m ethod was applied to an automotive body rear rail. The original design and a new design of equal volume with holes were compared for energy absorption.