Force and Moment Characteristics of a Rhombi Tessellated Non-Pneumatic Tire

There has been a recent spate of activities in the design of non-pneumatic tires (NPTs). The validation of a NPT's design is incomplete unless its performance is compared with an equivalent pneumatic tire. Apart from its static behavior, an evaluation of the tire's performance can be done by observing its force and moment (F&M) characteristics. In the present work, an NPT has been designed with an aperiodic rhombi tessellated spoke acting as the load bearing member, where the "unit cell'' design is based on the vertical, circumferential, and lateral stiffness offered by the structure. A three-dimensional finite element model has been used to capture the mechanics of load distribution in the spoke, contact patch, and variation of contact pressure distribution when the tire is subjected to different operating conditions. SIMULIA/Abaqus has been used to conduct static loading, acceleration/braking, and cornering analyses. The F&M characteristics have been extracted from these simulations and compared with those of a 165/70R14 passenger car tire. The variation in the vertical and circumferential stiffness based on the spoke geometry has also been highlighted. The use of conventional pneumatic tire's belts to alter the NPT's lateral stiffness, despite the tire behaving like a "bottom loader,'' adds uniqueness to the design. The NPT's capability to match the pneumatic tire's performance and the variability observed in the tire's F&M characteristics reiterate the freedom available in NPT design, thus providing the opportunity to have similar tires with varying performance characteristics.