Fatigue damage investigation and performance comparison analysis of non-pneumatic tires with different spoke structures

Non-pneumatic tires (NPTs) have attracted much attention due to their run-flat and maintenance-free advantages, but their spoke structures are diverse. At present, most studies adopted stress and strain to optimize the NPT structures, and few studies focus on the fatigue life of NPTs with different structures. In this work, we established ten two-dimensional (2D) finite element models of NPT. Under the same rim size, outer diameter and material parameters, the mass, stiffness, Mises stress, nominal strain, strain energy density (SED) and fatigue life were comprehensively analyzed under displacement control and load control conditions. Among them, the critical plane method and fatigue crack growth theory were used to predict the fatigue life of NPT. It is found that the ranking of the same structure under different indicators (Mises stress, nominal strain, SED and fatigue life) is quite different. Two three-dimensional (3D) NPT structures were further manufactured by 3D printing technology and analyzed considering the influence of heat build-up and thermo-mechanical coupling fatigue life. The comparison between simulation and experimental results shows that the model can effectively analyze the viscoelastic self-heating and fatigue failure of NPTs. This study proposed an NPT optimization design workflow from rapid analysis of 2D models to high-precision thermo-mechanical coupling analysis of 3D models and realized the quantitative evaluation of the NPT fatigue life.