Pantnagar Journal of Research

Abstract

The present study was undertaken to upgrade the existing traction laboratory of Agricultural and Food Engineering Department of IIT Kharagpur for the reduction in drudgery and easy operation. A vertical loading mechanism using hydraulics was designed to apply additional normal load up to 25 kN on wheel axle and remove 13 kN load from the initial load. The circuit used for applying force consisted of a fixed displacement pump, a 3-way, 4-port directional control valve, a relief valve and a double-acting cylinder. Load transducer based on proving ring for 40 kN load bearing capacity was developed. The ring was calibrated to get a relationship of voltage and load. The calibration was taken both tensile and compression modes. Vertical loading mechanism by hydraulic was validated in both static and dynamic conditions. Validation of hydraulic normal loading was done with test tyres under static and dynamic conditions. The vertical load was varied from 7.85 kN to 10.30 kN using a hydraulic loading mechanism under both static and dynamic conditions. A bias-ply tyre and a radial-ply tyre, each of 13.6x28 sizes were selected under this study in soft 2 soil conditions. The soil cone index was maintained between 0.6 to 0.8 N/mm . Under the static condition, the data show that the maximum load which could be added was 4.75 kN and the corresponding retracted load at the same pressure was 4.69 kN. There was only 3% difference in ring transducer and pan balance reading under dynamic condition, an average of 1.02% to 6.26% difference in load during the entire length of travel w.r.t initial load was found for both bias and radial-ply tyre under different pull up to 20% slip. There was no significant difference was found between initial vertical load and average vertical load during travel as the p-value (calculated probability) was found 0.30 (> 0.05) using t-test available in SAS 9.3.