The tire-ice interaction is a highly complex phenomenon, which has a direct influence on the overall performance of the pneumatic tire. From tire-terrain interaction dynamics, it is evident that icy road conditions and tire operational parameters play a vital role in determining the overall performance of the vehicle. With the reduction of traction available at the surface in icy conditions, the dynamics of the vehicle becomes more unpredictable, as the system can become unstable. In order to design an appropriate safety system, the tire-ice interaction must be closely investigated. Since the tire is the part of the vehicle that is in direct contact with the terrain during operation, it is critical to have an in-depth understanding of the contact mechanics at the contact patch.
This study has led to the development and validation of an existing tire-ice model to further improve the understanding of the contact phenomena at the tire-ice interface. Experimental investigations led to a novel measurement technique in order to validate the semi-empirical based tire-ice contact model.
The Advanced Tire-Ice Interface Model serves to simulate the temperature rise at the contact patch based on the pressure distribution in the contact patch, thermal properties of the tread compound and of the ice surface. Since its initial development, the advanced model is now capable of simulating the thin water film created from the melted ice, the prediction of tractive performance, the estimation of the viscous friction due to the water layer, and the influence of braking operations including the locked wheel condition.
Experimental studies, carried out at the Terramechanics, Multibody, and Vehicle Systems (TMVS) Laboratory, were performed on the Terramechanics Rig. The investigation included measuring the bulk temperature distribution at the contact patch in order to validate the temperature rise simulations of the original Tire-Ice Model. The tractive performance of a P225/60R16 97S Standard Reference Test Tire and a 235/55R-19 Pirelli Scorpion Verde All-Season Plus XL were also investigated during this study. A design of experiment was prepared to capture the tire tractive performance under various controlled operating conditions. / Ph. D. / Icy road conditions and tire performance play a vital role in determining the overall performance of a vehicle. With the reduction of traction available at the surface in icy conditions, the vehicle becomes more unpredictable and can become uncontrollable. In order to design an appropriate safety system, the tire-ice interaction must be closely investigated. This research aims at enhancing the understanding of the tire-ice contact interaction at the contact patch through modeling and experimental studies for a pneumatic tire traversing over solid ice.
Prior work in the laboratory produced a Tire-Ice Model (TIM) with the purpose of estimating the friction at the tire-ice interface. The current work builds on that study, resulting in the Advanced Tire-Ice Interface Model (ATIIM). This model predicts the temperature rise at the tire-ice interface based on the measured pressure distribution and the thermal properties of the tire and of the ice surface. This model allows a more thorough investigation of the tire-ice interface, being capable of predicting the height of the thin water film created from the melted ice, the prediction of tractive performance of the tire, the estimation of the viscous friction due to the water layer at the contact interface, and the influence of braking operations, including the locked wheel (skid) condition.
Experimental studies were carried out at Terramechanics, Multibody, and Vehicle Systems (TMVS) Laboratory on the Terramechanics Rig. The experimental investigation included measuring the temperature at various points at the tire-ice interface in order to compare the temperature rise predicted using the ATIIM. Furthermore, the tractive performance of the tire was also investigated by examining different conditions of vertical tire load, tire inflation pressure, and ice surface temperatures as well as various steering configurations set by the user.
In addition to investigating the performance at the tire-ice interface, a vehicle model in which the front wheels are considered as one (and the same for the rear wheels), often referred to as the bicycle model, is studied while traveling over smooth ice. To ensure the accuracy of the vehicle simulation, the tire model chosen must account for the actual conditions in which the model will operate. In this study, the ATIIM is incorporated in empirical tire models commonly used in industry and used in conjunction with a vehicle model to accurately predict the behavior of the vehicle when operating on smooth ice.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/82873 |
| Date | 23 April 2018 |
| Creators | Jimenez, Emilio |
| Contributors | Mechanical Engineering, Sandu, Corina, Burdisso, Ricardo A., Terziyski, Jan, Taheri, Saied, Ferris, John B. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/x-zip-compressed |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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