An efficient three-dimensional tire model for predicting spindle loads.

Abstract

For vehicle dynamics simulations, tire models that can accurately predict spindle loads resulting from durability road events, such as curb or chuckhole impacts are lacking. In this dissertation, an efficient three-dimensional tire model is presented for use in simulating such events. The tire model comprises three main parts. First, the sidewall is modeled with finite elements based on the precomputed response of a nonlinear substructure that characterizes the force-deflection behavior of the sidewall. Thus, all of the DOF on the sidewall are effectively condensed out of the model. Second, the tread is modeled with nonlinear shell elements. Finally, contact is modeled as a yield surface based on an orthotropic elastic foundation coupled with an isotropic Coulomb friction law. The tire model is recast in an Arbitrary Lagrangian Eulerian context, thus allowing the tire to convect through the mesh. This enables the contact patch to be refined in an otherwise coarse mesh and, therefore, greatly reduces the size of the model. In order to properly model the lateral forces of a rolling tire, tread block compliance must be accounted for. The contact compliance is, therefore, treated as a convected property. An update procedure allowing it to be treated as an internal state vector is utilized, thus further reducing the size of the model. Finally, the tire model's computational speed and fidelity were assessed. The model's response was validated using a diverse set of static and dynamic experiments performed for this study.