Graph and heuristic based topology optimization of profiles made of fiber reinforced plastic in crashworthiness applications
Fiber-reinforced plastic composites offer a high specific stiffness and, depending on the load, a high specific energy absorption, which makes them interesting materials for crash applications when low masses are desired. Due to the anisotropic material behavior and a wide range of options for the layer stack including the fiber orientations, the structures can be designed individually in accordance with the load. The question arises as to how engineers can be supported in the complex design process in order to make the most use of the design freedom in crash applications. Optimization methods can be used in many areas to support design processes and to find the most suitable topologies, shapes and layer stacks. However, in crash applications most optimization methods cannot be used or are limited to special disciplines, since the nonlinearities in the crash load cases make the use of sensitivity-based algorithms impossible or too resource-intensive. The Graph and Heuristic based Topology Optimization has been developed for optimizing the topology and shape of crash-loaded extruded aluminum profiles. This work describes the extensions necessary to optimize fiber composite profiles. Multi-chamber profile structures are treated, which are built up from individual profiles manufactured in a tape winding process and bonded together by adhesives. The topology of the profile cross-section and the layer stack are optimized using heuristics that evaluate the results of a crash simulation and suggest structural improvements based on these results. The heuristics are activated for each initial design of an iteration individually and in competition with each other. Over several successive iterations, in which the best designs are passed on to the subsequent iteration, complex designs can be created. In addition to introducing the geometry description, the generation of the finite element models, the heuristics and the optimization process, several application examples are presented in which different crashworthiness structural responses are optimized under compliance with various restrictions and manufacturing constraints. The mass, intrusion and maximum force is minimized in several optimizations. By using the methodology, fiber composite profile structures can be designed in crash applications and thus a contribution to facilitate their use is made.
Shaker Verlag, Düren. ISBN: 978-3-8440-8884-7
