Particle and geometry scaling of the hysteretic spring/linear cohesion contact model for discrete element modelling of soil-tool simulation

Abstract. Modelling of soil-tool interaction is a complex process due to the variability within a given soil profile, non-linear behavior of the soil and the dynamic effects of soil flow. An approach which is able to realistically simulate the tillage process is discrete element method (DEM). Successful DEM simulation of soil tool interactions for agricultural applications has been shown possible with the use of a hysteretic spring contact model integrated with a linear cohesion model (HS/LC). Due to current computational limitations, particle sizes used in DEM tend to be significantly larger than that of the actual soil grains. Mechanical properties used in the DEM contact model must be corrected via calibration in order for the bulk behavior of these larger than actual particles to achieve accurate validated results. Ideally, these calibrations are done with the actual geometry of interest but this is not always feasible for large agricultural machinery. If particles and geometry used with the HS/LC contact model can be scaled this would enable smaller scale calibration tests to be run in the laboratory, whilst being able to simulate larger scale equipment without a compromise in simulation accuracy. A range of calibration tests and simulations were undertaken using different scale particles and geometries. The results showed that it is possible to scale particles and geometries without sacrificing the accuracy of the simulation results.