Topology optimization of wheel spoke cavities for lightweight design under bending fatigue and impact load cases

This paper presents a Multi-Load-Case topology optimization framework for aluminum alloy wheels to overcome the limitations of empirical rear-cavity lightweight designs. To balance structural integrity and mass reduction without altering the aerodynamic outboard styling, a region-constrained topology optimization was conducted. By employing a compromise programming method based on strain energy ratios, the weighting coefficients for bending fatigue and 13° impact load cases were scientifically calibrated. Furthermore, manufacturing constraints, including a 10 mm minimum member size and draw directions, were incorporated to ensure direct compatibility with conventional casting. The results demonstrate that the optimized depth-gradient cavities successfully reduced the peak von Mises stress for bending fatigue by 19.25% (from 133.9 to 108.13 MPa) and for the 13° impact by 14.57% (from 74.63 to 63.76 MPa), alongside a slight mass reduction of 0.53%. This approach offers a mathematically rigorous and industrially viable paradigm for the multi-objective lightweight design of high-performance automotive components.