A Tire Model for Very Large Tire Deformations and its Application in Very Severe Events

The full vehicle simulation on durability proving grounds is a well established technique in the pre-development process of passenger car manufacturers. The respective road surfaces are designed to generate representative spindle loads and typically include events that will result in large tire deformations. Depending on manufacturer and the combination of vehicle size and wheel properties, these deformations can be so large that the tire belt and/or sidewall have contact with the rim crown (protected by the tire sidewall). The current tendency to low-aspect ratio tires reduces the available deformation capability of the tire while simultaneously introducing larger nonlinearities in the sidewall behavior (see [ 2 ]).

This paper is based on a co-development project between Fraunhofer LBF and Honda R&D and is dealing with the development of a tire model, which can accurately handle very large deformations of the tire up to misuse-like applications. The model is based on the LBF tire model CDTire, where several nonlinear extensions of the belt and sidewall model have been implemented to accurately capture the large deformation behavior. These model extensions are also taking the belt/sidewall and sidewall/ rim contact into account. The paper is a consequent continuation and improvement of first modeling and validation efforts previously published in [ 1 ], which at that time were based on quasi-static tire stand-alone measurements. The main innovations are related to the implementation of a new dynamic test rig specially designed by Fraunhofer LBF for large deformation tire testing. With this test rig, new impulses could be derived for the modeling and for the parameter identification procedure. Additionally, first full vehicle simulation results of a very severe event are shown to validate the method of approach, with comparisons to both the respective measurements and the simulation results without the model extensions. The simulations and the related measurements have been performed by Honda R&D and have not been available in [ 1 ].