Bekker and Wismer-Luth Models Assessment in Estimation of Tire Rolling Resistance in Comparison to Experimental Tests

There are different methods in order to model soil-wheel interaction which Bekker equation and Wismer models are two of them. These models have been selected in this study for tire rolling resistance prediction and comparison with experimental tests. Using an appropriate model for accurate prediction of rolling resistance, is useful for energy management. In this study, soil power-sinkage modules related to Bekker model were obtained. In this way, a series of plates with different widths was pushed into the soil while the force and corresponding sinkage were being measured. The soil cone index was recorded using a penetrometer in several replications to compare the rolling resistance calculated by both models and from experimental data. The experiments were performed with a single-wheel tester in controlled conditions at three levels of tire pressure and vertical load. The vertical load on the wheel was varied during the test, but its travel speed was kept constant at 2.3 km.h-1 . The results showed that Wismer model in all experiments had better ability to estimate rolling resistance than Bekker model. Bekker model with higher tire pressure provided better estimate for rolling resistance, since the wheel had been turned almost into a rigid wheel.