Investigation of the Spoke Lateral Thickness Effects on Non-pneumatic Tire Radial and Lateral Stiffness

Due to the excessively high lateral stiffness of honeycomb NPTs, which contradicted vehicle handling stability requirements, and the importance of radial stiffness for maintaining load-bearing capacity, coordinated optimization was necessary. This study investigates the impact of lateral spoke thickness on the radial and lateral stiffness of honeycomb non-pneumatic tires (NPT). The NPT model was evenly segmented, and different spoke thicknesses were set. Latin Hypercube Sampling was used to generate sample points to explore the effect of spoke thickness gradients on lateral and radial stiffness. Using the generated sample points, two surrogate models (RSM and RBF) were constructed, and NSGA-II was employed to solve the multi-objective optimization problem. The Pareto-optimal set with the minimum lateral stiffness was obtained while maintaining the original radial stiffness. Results showed a significant reduction in lateral stiffness, with initial NPT-1 at 449.17 N/mm, and optimized NPT-OP_RSM and NPT-OP_RBF at 409.52 N/mm and 407.42 N/mm, respectively, representing reductions of 8.83% and 9.29%. Vehicle handling and steering characteristics can be significantly enhanced. A better balance between lateral and radial stiffness was achieved in the optimized NPTs, with superior performance in lightweight and maximum spoke stress demonstrated, providing valuable references for the design of non-pneumatic tires.