The Review of Selected Non-Pneumatic Tires Properties-Mechanical Properties: Radial, Longitudinal, Lateral Stiffness,...

Nowadays, attempts to commercially apply non-pneumatic tires (NPTs) in a wide range of vehicles can be observed. These types of wheels use a specific structure and material selection to mimic the function of compressed air in pneumatic tires (PTs). This paper reviews the mechanical properties and vehicle applications of non-pneumatic tires. This review will provide information about the influence of the shape of the radial, longitudinal, and lateral characteristics, as well as the possibility of selecting contact pressure values at the wheel design stage and the influence of the type of elastic structure on the concentration of pressures in the contact length. The radial characteristics of non-pneumatic tires depend on the type of elastic structure. The spoked elastic structure will be characterized by greater displacements compared to the cellular structure, which will reduce radial stiffness. The radial stiffness of non-pneumatic tires is increased by increasing the number of elastic structure elements and their thickness and decreasing their length. The longitudinal stiffness of non-pneumatic tires increases with the number of elements forming the elastic structure and with the elastic structure's lack of susceptibility to circumferential deformation. Spoked non-pneumatic tires will have lower longitudinal stiffness compared to cellular non-pneumatic tires. The elastic structure is characterized by a low susceptibility to lateral deformation, which contributes to the high lateral stiffness of the non-pneumatic tire. Non-pneumatic tires have a limited ability to shape the contact patch parameters, which mainly depend on the vertical load and the shape of the tread area. The type of band used will influence the formation of contact pressures. An isotropic elastomer used in a shear band will cause pressure concentration at the ends of the contact length. A more uniform pressure distribution is achieved by using a laminated elastomer.