DEVELOPMENT OF A NEW OFF-ROAD RIGID RING MODEL FOR TRUCK TIRES USING FINITE ELEMENT ANALYSIS TECHNIQUES
Open Access
- Author:
- Slade, Jeffrey Lawrence
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- July 24, 2009
- Committee Members:
- Dr Moustafa El Gindy, Thesis Advisor/Co-Advisor
Dr Moustafa El Gindy, Thesis Advisor/Co-Advisor
Kevin L Koudela, Thesis Advisor/Co-Advisor - Keywords:
- Rigid ring model off-road truck tire finite elemen
- Abstract:
- Finite Element Analysis (FEA) is a powerful tool which allows researchers to use computers to quickly perform simulations of many complex physical objects. In this thesis, non-linear three dimensional FEA models are developed using PAM-CRASH to perform simulations of heavy truck tires running on both rigid surfaces and soils. These models include an FEA truck tire model and an elastic-plastic FEA soil model. The FEA models are then used to calculate parameters for a new semi-empirical off-road rigid ring model. An FEA truck tire model of a Goodyear RHD 315/80R22.5 drive tire for tractor semi-trailers is generated and the properties are tuned to match the manufacturer’s specifications. Simulations are performed under typical loading conditions to establish the behavior of the tire. An elastic-plastic FEA soil model, designed to represent sandy loam, is developed using material properties from published data and is validated using a number of previously published techniques. The construction of the tire and soil models and the methods used for validation are explained in detail in this thesis. A comparison between the tire running on rigid road and soft soil is made by performing various simulations for both cases. A new semi-empirical off-road rigid ring tire model is developed as a simplified model to describe the behavior of a heavy truck tire running on soft soil. This model is a modification of the rigid ring tire model developed by Pacejka and Zegelaar and includes additional parameters to incorporate the flexibility of the soil. Rigid ring parameters for the Goodyear RHD 315/80R22.5 truck tire are calculated for both the on and off-road rigid ring models. The results show that, in general, for a tire running on a sandy loam the motion resistance coefficient is approximately three times higher than on rigid road. The longitudinal slip stiffness is about a factor of four lower for sandy loam than for rigid road. This indicates that the available tractive force on sandy loam is about one-fourth of the available tractive force on rigid road. Interestingly, the longitudinal, or tractive force, appears to continue to increase with slip on sandy loam, while the tractive forces on rigid road level out after reaching a peak around 20% slip. When the tire and soil model is run at high slip angle it is noticed that the soil begins to ‘build up’ in front on the tire, causing an additional lateral force due to the pushing of the soil. Utilizing well validated and robust FEA models to predict the off-road behavior of tires may reduce the need to perform physical experiments, thereby reducing the cost and time required to obtain results and affect design changes. The off-road rigid ring model can be used in industry for full vehicle simulations for durability testing and structural dynamics. It is safe to assume that the use of finite element analysis in research and development will continue to rise as the available processing power of computers increases and become cheaper.