Tractive Performance of Rigid Wheel in Granular Media Using Coarse-scale DEM Models

Jelinek, B., Card, A., Mason, G. L., James, T., Grebner, K., Skorupa, T., & Priddy, J. (2023). Tractive Performance of Rigid Wheel in Granular Media Using Coarse-scale DEM Models. Proceedings of the 16th European-African Regional Conference of the ISTVS 2023. Lublin, Poland: ISTVS. DOI:10.56884/HITS7216.

Understanding the interaction between wheel and granular media in variable loading conditions is critical for prediction of net traction of wheeled and tracked vehicles in off-road environments. The discrete element method (DEM) is routinely used for modeling vehicle performance, but although simulations seem realistic, 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 the net traction, gross traction, and sinkage of a wheel operating in sand. Laboratory soil-bin measurements, serving as a reference for DEM simulations, were taken from physical experiments by Shinone et al. [2010], examining a 165/60R13 wheel with constant circumferential velocity of 97.6 mm/s and vertical contact load of 980 N operating in powered conditions under slips in the range of -5.9% to 54.8%. The set of ten DEM models for soil particles and particle-box interaction was a subset of the Generic Material Model (GEMM) database from Altair®'s EDEMTM software package, choosing the best match to the particle size, bulk density, and angle for repose for dry sand. Parameters for wheel-particle interaction were taken from the GEMM database and from the tire-soil parameter set used by Hu et al. [2021]. Given large particle size and no additional calibration of the DEM model, a good qualitative agreement for the gross tractive effort and sinkage is encouraging. The largest discrepancy is observed for the net tractive effort at large slip. A need for smaller particle size and further calibration are suggested for a future effort.