Topology optimization is a mathematical method used to optimize material layout within a given design space, considering loads, boundary conditions, and constraints, with the goal of maximizing system performance.

Key Highlights:

• This study used topology and free-size optimization to design a lightweight rear rail for an EV.
  Step 1: Topology optimization determined the rib pattern.
  Step 2: Free-size optimization reduced material thickness.
• The rear rail is a key aluminum casting in the BIW welded directly into the structure. Full BIW analysis is required for modal and stiffness checks but this is computationally expensive. Super element modeling was applied, linking the rear rail to the BIW at weld points. This enabled faster, accurate optimization and reduced computational cost.
• The result: 30% weight reduction in the rear rail with performance maintained. This approach shows super element modeling is a scalable, efficient method for lightweight EV design.