טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentBoroda Alex
SubjectFinite Element Modeling of Agricultural Tires
DepartmentDepartment of Mechanical Engineering
Supervisor Professor Emeritus Pinhas Bar-Yoseph
Full Thesis textFull thesis text - English Version


Abstract

Analyzing a finite element model of an agricultural tire is one of the challenging problems in computational mechanics. It is a very complex and nonlinear contact problem, involving a complicated geometry, composite materials, dynamic loading conditions, large deformations and interaction with different substrates. The current work is focused on the hard surface. For better understanding of tire manufacturing process and its complexity, an overview of tire technology is presented in this work. It includes the tire structure, the tire types, the general manufacturing process of tires and the new tire development process. The major goal of the project is to create a full three-dimensional model of agricultural tire in its entirety, and use this model for the prediction of tire behavior through geometric dimensions and tire stiffness on the hard surface. The secondary objectives are as follows:

      Create a computational model as a tool to predict performance and design of the agricultural tires.

      Verify the finite element model by the experimental results of the tire.

      Examine the effect of the belts angle, on the relevant parameters such as tire inflated geometry, tire radial deflection and tire footprint on the rigid surface.

A model of finite element analysis for the examination of tire inflated geometry, the tire radial deflection and the contact area of a tire with a rigid surface are presented in this work. Two different models of a tire, Smooth/Ribbed and Treaded models have been prepared by using commercial finite element program - ABAQUS. The differences and advantages of both models are presented and discussed. The chosen model structure and the preparation of all the stages of the model are described in the presented work. The results of tires with the same structure except the different values of the belt angles, which were obtained from the finite element model, were compared to experimental ones, confirming the validity of the model. For this purpose four different experiments were held, including a total of twelve tires. Equipment and methods used for experimental determination of the relevant parameters are shown. Examples of a material properties definition have been presented. Differences between numerical results and experimental results are discussed. It has been shown that the finite element model which is presented provides a pretty good correlation between numerical and experimental results. It has been shown that the "Treaded model" is much more suitable for the agriculture applications than the "Ribbed model" from the point view of footprint and pressure distribution results. It is concluded that a computational model which is presented, can be used as a tool to predict design of the agricultural tires. For the future works of the agricultural applications, the main interest will be in the field of tires after their manufacturing, such as; features of interaction between tire and soil, heat development, and tire behavior on the road and in the field.