Team of the chair
Dr.- Ing. Johannes Sperber
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Graph and Heuristic based Topology Optimization of crash structures under
axial compression loads
Due to their superior energy absorption capabilities, extruded profile structures
are broadly used as crash structures in the front and rear ends of vehicles. For their
efficient crash design, topology optimization methods can play a key role. Due
to the occurring nonlinearities in vehicle crash simulations, established topology
optimization methods are usually inapplicable. Therefore, new methods such as
the Graph and Heuristic based Topology Optimization (GHT) were developed.
This method uses mathematical graphs for a simplified description of the profile
cross-section. Furthermore, competing heuristics based on expert knowledge are
used to modify the topology. These heuristics were developed for the optimization
of profile structures exposed to lateral compression and/or bending loads (e.g.,
vehicle rocker under pole impact).
However, for profile structures under axial compression loads (e.g., crash box
in front crash), progressive buckling is usually the desired mode of deformation.
Compared to laterally loaded profile structures, different considerations must
be made to provide high specific energy absorption capabilities while initiating
and maintaining a robust crash behavior. To address these challenges, a new set
of heuristics is developed in this work. Since the structural responses of profile
structures under axial loads can also be sensitive to small variations in the finite
element model, the automated model creation process is enhanced to consider
geometrical details. Furthermore, trigger mechanisms are established to control the
structural behavior. Hence, the method allows for a parameter-based application
of trigger mechanisms.
The effectiveness of the topology optimization method is demonstrated in various application examples. The method proves to be suitable for an industrial
development environment due to the implemented manufacturability checks, the
consideration of geometrical details as well as its effectiveness regarding the
required amount of function calls
