Optimization of Static Three-Dimensional Stiffness of Non-Pneumatic Tire with Composite Spokes Based on Response Surface Method

This study aimed to investigate the relationship between the static stiffness of non-pneumatic tires (NPTs) and the design parameters of composites spokes and shear bands using the finite element (FE) method. The stress–strain curve of the rubber material was fitted using the neo-Hookean constitutive model. Subsequently, key design parameters, including the reinforcement plate thickness and constitutive parameters of the spoke and shear band materials, were selected based on the NPT structure. FE simulations were performed on multiple sets of different parameter design schemes for the NPTs, and polynomial models for the vertical, lateral, and longitudinal stiffnesses were established using response surface analysis. The sensitivity analysis results indicated that the thickness of the reinforcement plate significantly influenced the three-dimensional stiffness, whereas the constitutive parameters of the spoke and shear band materials had a relatively minor impact. Finally, multi-objective optimization was employed to determine a design scheme with maximum longitudinal stiffness while ensuring vertical load-bearing capacity. Under the premise of ensuring the vertical load-bearing capacity, the longitudinal stiffness increased by 39.1% and 32.9% in the forward and backward directions, respectively. This method can be used to predict the three-dimensional stiffness of NPTs under different design parameter schemes or to optimize the setting parameters of NPTs based on the desired target stiffness, facilitating the rapid design of the three-dimensional stiffness of NPTs.