Abstract
Research on soil-wheel interaction is essential in studies of motion resistance of narrow wheels of agricultural machines. The aim of this research was to study the effects of soil moisture content and tyre inflation pressure on motion resistance of narrow wheels using a locally developed single wheel test rig. A single wheel Test Rig facility was developed at Federal University of Technology, Akure. It consists of a soil bin, carriage, single narrow wheel tester, trolley and drive system. An existing indoor soil bin facility was equipped with a soil bin which dimension was 9.76 m length x 1.98 m width x 0.92 m high. The single-wheel test facility was utilized to investigate the effect of tyre inflation pressure and vertical load on motion resistance of wheel. Two narrow wheels of 90/10-10 in width, IRC MB90 tyre were used as the test wheels on clay soil and were separately installed on a carriage that traversed the length of soil bin. Two inflation pressures of 274 kPa and 380 kPa and four levels of vertical load applied on wheel (i.e. 15, 20, 30, and 40 kg) were examined at two different soil moisture conditions (bulk density of 1.58 g/cm3 and 1.55 g/cm3, soil moisture content of 8% and 10% dry basis and soil penetration resistance of 1.02 MPa and 1.5 MPa). Exponential regression was obtained for the two wheels to check for linearity at different moisture content, R2 value for test wheel 1 with inflation pressure of 270 kPa at 8% moisture content was 0.9974 while that of inflation pressure of 380 kPa at 10% moisture content was 0.9952; also for test wheel two (2) R2 value was 0.9977 and 0.9914 at moisture content of 8% and 10% respectively, this shows for test wheel 1 with inflation pressure of 270 kPa at 8% moisture content showed more motion resistance compared to motion resistance of test wheel 1 at inflation pressure of 380 kPa and 10% moisture content, while for test wheel 2 with inflation pressure of 270 kPa showed low motion resistance at 8% motion content. The effect of different inflation pressures and vertical loads on the motion resistance of the narrow wheels has been investigated under different moisture content (8% and 10%). The contact area for all tests was in the range of 309-330 cm2, average contact pressure increased nearly linearly with increase in vertical load and increase in inflation pressure The research provides data that are relevant in the study of soil-wheel interaction.