Fundamental Study on Pavement-wheel Interaction Forces through Discrete Element Simulation

Abstract

The primary loads on the pavement surface come from the pavement-wheel interaction. This paper presents a discrete element modeling approach for interpreting the underlying mechanism of the pavement-wheel interaction forces, including the vertical contact force and the contact frictional force. As expected, the actual interaction forces are usually controlled by various factors such as properties or characteristics of pavement and tire materials, speeds, acceleration and deceleration of vehicles, and damping properties at the interaction surface. This research emphasized motion features of vehicles including acceleration, deceleration, and steadily moving, as well as the material damping ratio at the interaction interface. In order to eliminate impacts from the other factors, this study utilized an idealized discrete element model, which consists of three parts: a smooth surface, a driving wheel, and a mass. The smooth surface was used to simulate the pavement surface while the driving wheel and mass represent a vehicle wheel and its corresponding mass, respectively. Obviously, both the actual pavement and vehicle loading conditions were idealized: variation of pavement roughness and vehicle loading conditions was eliminated for analyzing mechanism underlying the wheel-pavement interaction. Through this study, it was found that: 1) during wheel movement, the interaction forces were not constant but fluctuated around their averaged values; 2) the average frictional force was close to zero when the wheel is steadily moving, while it was non-zero during its acceleration and deceleration; 3) the observed vertical contact forces had similar trends to those obtained from the finite element modeling.