Evaluation of Agricultural Tire Traction Prediction Models Using a Single Wheel Tester

Abstract

A study was conducted to analyze and evaluate Wismer-Luth and Brixius equations in predicting net traction ratio, gross traction ratio, motion resistance ratio and tractive efficiency of a high-lug agricultural tire. The experiments were conducted on a clay loam soil in an indoor Shiraz University tire traction testing facility. The experiment was performed by running a 5.00-12 high lug agricultural tire at two selected inflation pressures (i.e., 103 and 207 kPa), three vertical load (i.e., 130,160 and 190 kgf) and three levels of drawbar pull (0, 10 and 15 kgf). Regression analysis was employed to determine the best prediction equation explaining the tire gross traction ratio and net traction ratio. The logarithmic model was found suitable based on the coefficient of determination and residuals. Also, Comparing the test values with the values obtained by the models showed that Wismer-Luth model gave smaller error in prediction of gross tire traction ratio, while, the values of predicted net traction ratio given by both models were significantly different from the test values. The difference between the predicted and test values of gross traction ratios were between 13 to 24 percent, while those of net traction ratios varied between 45 to 93 percent. Based on the collected experimental data new models were developed for prediction of gross and net traction ratios. The results of evaluation of the new models showed good prediction of both gross and net traction ratios.