A Topology Optimization Interface for LS-Dyna

Topology optimization is more and more applied in industrial appli- cations and has shown to be a valuable tool for the design of mechanical structures. However, few applications in topology optimization deal with nonlinear or transient problems. In order to enhance research for this kind of problems, a topology optimization interface for LS-Dyna was de- veloped. It facilitates to couple an optimizer to the solving abilities of LS-Dyna by bridging the gap to the LS-Dyna in- and output files. In the first step, an input deck and the parts subject to the optimization are specified and the input deck is read. The interface supports the genera- tion of new input decks depending on the design variables, the scheduling of LS-Dyna jobs on a computation cluster, and the extraction of simula- tion results. Common topology optimization methods parameterize every mesh element by a density variable and assign material parameters to the elements accordingly. For this purpose the interface provides a set of ma- terials with stepwise scaled parameters of the original material. Several types of scaling methods can be applied that also account for very low density values and keep the number of materials and the relative quanti- zation error low. Depending on the design variable the correct material model is chosen for each element. With this functionality, material in- terpolation schemes may be applied in the optimization, presently for the MAT 001 and MAT 024 LS-Dyna material models. Elements may also be removed and re-added to the mesh in order to apply discrete topology op- timization algorithms. In this paper the concept and basic functionality of the interface are described. Results of two different topology optimization methods for example problems are provided.