Lightweight Wheel Design Through Shape Optimization with Structural Constraints

The wheel rim is an annular, thin-walled structure featuring complex geometry and is subjected to multiple load cases, including radial, rotary, and impact scenarios. Achieving an optimal balance between mass reduction and structural performance remains a significant challenge in modern vehicle wheel design. Aero-efficient vehicles demand lightweight backbone wheels capable of accommodating aerodynamic covers without compromising handling, steering precision, or overall performance. In this study, shape optimization is applied to an 8-spoke truck wheel with the goal of minimizing mass while enhancing lateral stiffness and ensuring that stress constraints are satisfied under all critical load cases. A three-dimensional finite element model is developed and evaluated under realistic radial, rotary, and impact loading conditions representative of industry validation tests. The optimization process fine-tuned the spoke geometry using symmetric shape domains and carefully defined perturbation vectors, while preserving styling intent, bolt pattern, and brake packaging constraints. Lateral stiffness was evaluated using a frequency-based formulation derived from modal and frequency response analyses, while grid stress responses served as robust optimization constraints. The resulting optimized wheel achieved a mass reduction of approximately 5 percent, a lateral stiffness increase of approximately 30 percent, and a 6 percent rise in the first drum-mode frequency.