The Discrete Element Method for Vehicle-Terrain Analysis

Peters, J. F., Vahedifard, F., Jelinek, B., Mason, G. L., & Priddy, J. D. (2019). The Discrete Element Method for Vehicle-Terrain Analysis. ISTVS-2019. PRAGUE: ISTVS.

Abstract

Numerical vehicle performance simulations can be used to better interpret field tests and can give preliminary data for vehicles still in the planning and design stage and no physical prototype yet exists. Although high-fidelity models exist for vehicle mechanics, vehicle-terrain interaction is still in its infancy. The discrete element method (DEM) is an increasingly popular method to model complex mechanics of wheel-terrain interaction on unpaved surfaces. This paper describes recent work with very large-scale DEM computations for subgrade modeling. The DEM inherently captures significant phenomena such as localized shear deformation, friction-dependent resistance, and soil dilatancy, all items difficult to capture using continuum-based methods. The principal limitation of DEM is the large number of particles required to achieve a reasonably small ratio of discrete element radius to tire size within sufficiently large test bed dimensions. Parallel Computing technology has advanced to a point that minimal computing requirements can be met. Comparing simulated results to those in the extensive DROVE database demonstrates the accuracy of traditional drawbar-pull tests and allows evaluation of adequacy of particle size, test bed dimensions. Issues remain concerning calibration to achieve realistic engineering properties, placement density and use of cone penetration simulations to assess subgrade strength. An investigation is underway on simulations of transient traction development including transitions during reversal of slip.