Structural optimization with manufacturing considerations

Abstract

Product design has traditionally been done in a sequential fashion. This often requires extensive iteration between product and manufacturing engineers to insure manufacturability long after the initial product design. Simultaneous engineering attempts to reduce design time by considering both the product and process from the earliest design stage. Toward this goal, we have extended a structural optimization program by incorporating manufacturability requirements for thin-wall beam type members formed by stamping. This was implemented using a new two-piece beam design element which accounts for thinning of the sidewalls during combined stretch and draw forming. Multiple material types and stamping processes are considered. Simple formulae for forming strain and elastic springback after stamping allow us to evaluate the formability of each beam member. The new capability was tested using both simple beam structures and a complete automotive frame structure. Minimum mass designs were then produced while considering both structural and formability requirements. In general, the mass of the optimal designs was near the mass of the same structures designed without manufacturing considerations. This was possible because of the additional design freedom offered by including the sidewall thinning effects.