Grid based contour parameterization and optimization of extruded aluminum profiles considering structural and manufacturing aspects

A multi-criteria optimization method for cross section shape optimization of extruded aluminum profiles under structural loads is presented. It is based on a new geometrical parameterization technique and can be applied to arbitrary cross sections, enabling large geometrical and topological changes. The constrained optimization problem is solved by a Sequential Quadratic Programming (SQP) algorithm, and Pareto-optimal solutions with regard to manufacturing effort and structural aspects are determined. For that purpose, a weighted objective function is used to include the manufacturing effort determined by a Manufacturing Effort Model (MEM) together with the mass of the profile into a stress, displacement and stability constraint optimization problem. The manufacturing effort is modeled through a fuzzy approach from qualitative linguistic statements of extrusion experts. The approach and its features are presented first by a clamped beam test example. It is then applied to larger practical cases. The results of an automotive roof pillar gained via the grid based contour optimization under operational loads are presented.