A New Method for Vehicle-Terrain Interaction Research

This paper presents a new method for off-road traction and mobility research. This is an experimental method, in which traction measures (drawbar pull, rolling resistance, and vertical load) are correlated with respective stresses in soil, generated under a vehicle's load: major stress S1, shear, and normal stresses in the octahedral stress system. A theoretical background for the proposed method lies in Bekker's traction equations, where tractive forces are correlated with stresses on a contact surface between a wheel and terrain. Substituting surface stresses with volume stresses is expected to result in a more precise description of wheel-soil interactions. The soil stress - tractive forces relationships were obtained in real-size field tests using wheeled and tracked vehicles, driven on sand, loess, and turf. Traction and soil stresses were measured simultaneously with the use of original measuring methods, which are described in the paper.