Measurement of Normal Stresses at the Soil-Tire Interface

Abstract

Agricultural energy usage is an important topic among agricultural industry producers, manufacturers, and regulators. The transfer of power between axle and drawbar is identified as one of the greatest inefficiencies in agricultural field operations. Understanding the stresses at the soil-tire interface would provide insight into the current state of tire traction development and data useful in developing future tire designs. This article presents a measurement system to quantify the normal stresses at the soil-tire interface of an agricultural tractor tire, thus making it possible to evaluate these stresses along the tire footprint. A normal stress measurement system was developed in the laboratory and tested in the field. Additionally, a dedicated data acquisition system was developed, tested, and validated in the field environment. Test results show the system capabilities as well as information on the challenges of drawing general, consistent conclusions concerning the stresses developed between a tire and the soil at field working speeds in agricultural soil.