Tractive performance of rigid wheel in granular media using coarse-scale DEM models

Abstract

Understanding interactions between wheel and granular media in variable loading conditions is critical for prediction of mobility of wheeled vehicles in off-road environments. The discrete element method (DEM) is routinely used for modeling vehicle off-road performance, but the method’s accuracy is often not fully established.In this work, the DEM modeling accuracy is assessed by the comparison of ten DEM soil models with laboratory soil-bin measurements of net traction, gross traction, and sinkage of a wheel operating in sand. Laboratory soil-bin measurements, serving as reference for DEM simulations, were taken from physical experiments by Shinone et al. (2010), examining a 165/60R13 wheel with circumferential velocity of 97.6 mm/s and vertical contact load of 980 N in varying slip conditions.The set of ten DEM models was selected from the Generic EDEM Material Model database from Altair®’s EDEM™ software package, choosing the materials matching the bulk density and angle of repose for dry sand.Given the large particle size and no additional calibration of the DEM models, finding overall reasonable match with the gross traction from lab measurements and identifying a material predicting the net traction with a satisfiable accuracy encourages further use, refinement, and calibration of the DEM-based soil models.