Wheel impact performance with consideration of material inhomogeneity and a simplified approach for modeling

The focus of this research deals with wheel impact testing. The test procedure SAE J175 is used to access the wheel impact performance, which involves a striker dropped freely onto the rim flange of the wheel. The wheel is mounted at a 13° incline and a tubeless tire inflated to 200 kPa is assembled with the wheel. Numerical implementation of wheel impact testing is essential to shorten design time, enhance wheel mechanical performance, and lower development cost. A numerical model of an aluminum wheel with its tire was developed. Impact simulations were conducted to investigate the stress and strain performance during wheel impacting. Material inhomogeneity of the wheel was taken into consideration by assigning different stress/strain properties to the hub, spoke, and rim regions of the wheel based on observations acquired from tensile test specimens extracted from the corresponding areas. Numerical predictions illustrate that the tire model is capable of transmitting impact loads like the actual tire. Due to the complexity and additional analysis time used for the tire model, a simplified approach of wheel impact testing without the tire portion was developed. In the simplified approach, a percentage of the striker kinetic energy was deducted to compensate for the tire absence. In an effort to accurately determine the amount of kinetic energy reduction equivalent to the actual tire performance, numerical simulations were conducted with 10%, 15%, 20%, 25% and 30% reductions of the initial striker kinetic energy. Comparisons of the numerical predictions with the experimental measurements of the impacted wheels illustrate that an approximate 20% reduction of the initial striker kinetic energy provides an effective method for simplifying the numerical modeling by eliminating the tire portion.