Finite element modeling of dynamic *impact and cornering fatigue of cast aluminum and forged magnesium road wheels

Numerical investigation of wheel dynamic impact and cornering fatigue performance is essential to shorten design time, enhance mechanical performance, and lower development cost. This dissertation focused on two objectives. First, finite element models of the dynamic impact test on a wheel and tire assembly were developed, which considered the material inhomogeneity of the wheel. The model complexity and resultant additional analysis time led to the development of a simplified approach for wheel impact testing without the tired. Comparison of the numerical predictions with the experimental measurements of wheel impact indicated that an approximate 20% reduction of the initial striker kinetic energy provides an effective method for simplifying the numerical modeling. Second, numerical prediction of wheel cornering fatigue testing was considered. Two numerical prediction methods were applied to simulate wheel cornering fatigue testing. The first method utilizes a static stress analysis with different bending directions applied to the hub. The second approach uses a dynamic stress analysis with the application of a rotating bending moment applied to the hub. The fatigue performance of the wheel was evaluated based upon the results from both the static and dynamic stress analyses. Using a Goodman linear fatigue failure criterion for multiaxial stresses, both the equivalent alternating and mean components of the combined stresses as well as the safety factors of wheel fatigue design were determined. The elements with low factors of fatigue safety were identified either by boundary constraints or by geometric stress concentration. Experimental testing results verified the numerical predictions. A design modification was applied to the forged magnesium wheel to improve its fatigue performance.*.;*This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation).