Modeling and analysis of off-road tire cornering characteristics

Abstract

Cornering performance characteristics of wheeled vehicles substantially rely on the forces/moments generated from interactions between pneumatic tires and terrains. Accurate models are thus required to predict these forces/moments to be employed in vehicle simulations for development and design. The goal of this dissertation research is to provide a virtual testing environment in Pam-Crash software as an alternative to actual tests for Finite Element Analysis (FEA) and Smoothed Particle Hydrodynamics (SPH) analysis of rolling tire interactions on deformable terrains. SPH method and hydrodynamics-elastic plastic material were used to simulate different soil types that are often utilized in vehicle-terrain interactions. Two pressure-sinkage and shear-strength experiments were used to calibrate the terrains. The simulation findings were compared with the measured data that showed good agreements. Furthermore, a detailed analysis of the rolling resistance coefficient and cornering properties of the tire over various terrains is presented, as well as the development of Genetic Algorithms (GA) to determine the mathematical relations for the cornering force, self-aligning moment, and overturning moment as functions of important operating factors. Cornering tests were performed for the RHD tire operating over the mud soil to examine the validity of the GA-based cornering force, self-aligning moment, and overturning moment relationships. It was concluded that the identified mathematical relations could provide very good estimations of the cornering characteristics under a broad range of operating conditions and soils.