Lightweight Body-In-White Design Driven by Optimization Technology

Structural optimization technologies are increasingly applied to lightweight automotive structural design. In a body-in-white (BIW) development project, optimization technologies are applied in three steps that are seamlessly integrated into engineering practice. By following a design-driven approach, an innovative design that was 50.65 kg lighter than the base design was achieved. First, topology optimization was used to investigate the optimal material distribution in a given design space, and helped in extracting the main load path, while considering crashworthiness, NVH, and static stiffness performance requirements. In the second step, the effective design of a beam cross-section and feasible joints was carried out based on optimization technology and expert knowledge. In this step, the deep involvement of manufacturing process experts on stamping and joint connection feasibility analysis increased the chance of success remarkably. The sensitivity analysis, topography optimization, and gauge optimization of the created draft 3D BIW frame comprised the last step before finalizing the initial design. The new design was validated by full load case simulations, including full vehicle crashworthiness analysis, mode frequency, and body mount point dynamic stiffness analysis, and BIW stiffness and component attachment stiffness analysis. The validation results indicate that the new BIW design achieves the performance goal, while being 13.3% lighter than the base design.