Lightweight Design Enabled by Innovative CAE Based Development Method Using Topology Optimization

Carbon neutrality has become a significant target. One essential parameter regarding energy consumption and emissions is the mass of vehicles. Lightweight design improves the result of vehicle life cycle assessment (LCA), increases efficiency, and can be a step towards sustainability and CO₂ neutrality. Weight reduction through structural optimization is a challenging task. Typical design development procedures have to be overcome. Instead of just a facelift or the creation of a derivative of the predecessor design, completely alternative design creation methods have to be applied. Automated structural optimization is one tool for exploring completely new design approaches. Different methods are available and weight reduction is the focus of topology optimization. This paper describes a fatigue life homogenization method that enables the weight reduction of vehicle parts. The applied CAE process combines fatigue life prediction and topology optimization. An adapted design for a differential case was found, which does not sacrifice strength or stiffness properties of the component. Despite the very limited freedom for design modification, an interesting solution that saves nearly 20% of mass could be obtained, which demonstrates the potential of this approach to help achieve carbon neutrality through material saving. Other properties such as bolt loosening, stiffness, and castability were also considered. Verification with finite element analysis, fatigue assessment, and testing of the original and optimized components were performed. The lifetime results for virtual and real testing match quite closely and prove the effectiveness of this fatigue life homogenization method. Fine tuning of the simulation was also performed. Local material characteristics were considered based on filling and solidification simulations for the cast process of the component.