A finite element analysis of pneumatic-tire/sand interactions during off-road vehicle travel

Purpose - The purpose of this paper is to carry out a series of transient, non-linear dynamics finite element analyses in order to investigate the interactions between a stereotypical pneumatic tire and sand during off-road vehicle travel. Design/methodology/approach - The interactions were considered under different combined conditions of the longitudinal and lateral slip as encountered during "brake-and-turn" and "drive-and-turn" vehicle maneuvers. Different components of the pneumatic tire were modeled using elastic, hyper-and visco-elastic material models (with rebar reinforcements), while sand was modeled using the CU-ARL sand models developed by Grujicic et al. The analyses were used to obtain functional relations between the wheel vertical load, wheel sinkage, tire deflection, (gross) traction, motion resistance and the (net) drawbar pull. These relations were next combined with Pacejka magic formula for a pneumatic tire/non-deformable road interaction to construct a tire/sand interaction model suitable for use in multi-body dynamics analysis of the off-road vehicle performance. Findings - To rationalize the observed traction and motion resistance relations, a close examination of the distribution of the normal and shear contact stresses within the tire/sand contact patch is carried out and the results were found to be consistent with the experimental counter parts. Originality/value - The paper offers insights into the interactions between a stereotypical pneumatic tire and sand during off- road vehicle travel.