Automated Derivation of CAD Designs from Topology Optimization Results

Topology optimizations are gaining track in many development processes, especially in designing large structural components such as railway car bodies. This paper proposes an automatic process to derive design proposals from SIMP topology optimization results in early product development stages. The topologies are interpreted as truss-like structures in order to be modelled using beam elements in FE or CAD applications. In a first step, a wireframe is extracted by using a voxelization approach with subsequent skeletonization and junction identification using flood-fill algorithms. The wireframe can already be used as a basis for a parametric CAD design since it follows the topology optimization result closely. In order to extrude beam sections along the wireframe axes, cross sections are extracted from the topology optimization result. This is done by first matching the geometric outline of a topology branch to basic shapes such as rectangles. These shapes are refined by identifying the load case of each branch which is achieved by evaluating the stress distributions in a branch of the topology optimization. The consolidated result is a model consisting of beam elements which can further be processed in an FE or CAD application. The process enables a faster design exploration in the early product development process with the goal of achieving lightweight designs