Graph and heuristic based topology optimization of crash-loaded profile structures made of joined sheet metals
Structural optimization makes a valuable contribution to vehicle development by designing lightweight, cost-effective, and safe vehicles. The classical methods for optimizing linear-statically loaded structures reach their limits due to the large number of different non-linearities and bifurcations in the crash simulation, so that they cannot be used or only to a very limited extent. The Graph and Heuristic-based Topology Optimization (GHT) developed at the University of Wuppertal has proven its worth in the optimization of crash-loaded profile structures. The method uses heuristics to modify the topology of the profile, thereby integrating or removing walls in the profile cross-section. The implemented manufacturing constraints, in combination with the graph representation of the cross-section, ensure that the optimized structures can be manufactured immediately without the need for geometry interpretation. The first applications for the GHT mainly focus on profile structures manufactured by extrusion, typically made of aluminum. This work develops the possibility of considering a new manufacturing concept for the GHT, where the profile structure consists of multiple sheet metal profiles, which are joined at flanges. This allows the use of metals, such as aluminum and steel alloys with higher strengths. The complexity of the individual sheet profiles can vary in the optimization, but only cross-sections that can be manufactured will be used. To meet this requirement, manufacturing constraints specifically for sheet metal design were developed. These include manufacturing constraints that consider the forming of sheets with a sheet metal bending process. Additionally, manufacturing constraints must consider the joining of sheets and ensure the accessibility of the joining tools. In terms of joining the focus is set on laser beam welding and resistance spot welding. For all simulated profiles it is ensured that there is a feasible joining sequence that enables the profile to be assembled.
Shaker Verlag, ISBN: 978-3-8440-9989-8
