Stress Analysis of Tractor Tire Interacting with Soil using 2D Finite Element Method

Soil compaction under tractors tires is becoming a major concern as larger machines are being used in recent years. The heavy duty off-road machines particularly those related to agricultural practices drastically compact the soil causing higher energy consumption and lower yield. The size and form of the tire and soil interaction as well as soil type are important in stress distribution. The objective of this study was to develop a model for soft soil responding to tire pressure and axel load using finite element (FE) technique. A 2D-axisymmetric Drucker-Prager material FE model was developed for analysis of soil behaviour under different load and tire inflation pressure. A 2D symmetric Moony-Rivilin model was also used for soil and tire interaction and compared with measured field response data available in literature. The maximum soil-tire pressure of 83.7 kpa was found for 70 kpa inflation pressure and 15kN axel load which were approximately 30% less than the stress at the tire contact patch in the field test as reported in the literature. Maximum vertical stress at contact area was 98.6 kPa for 150kPa inflation pressure and 15 kN axel load which was not statistically significant while comparing with 101 kPa previously reported 3D analysis. The maximum distributed stress was found at tire side wall. Results also showed that 2D axisymmetric model is able to monitor the soil-tire stresses with an acceptable accuracy.