Discrete element modeling of a vibratory subsoiler

[摘要] Vibrating a tillage tool is an effective way of reducing the draft force requiredto pull it through the soil. The degree of draft force reduction is dependent on thecombination of operating parameters and soil conditions. It is thus necessary tooptimize the vibratory implement for different conditions.Numerical modelling is more flexible than experimental testing and analyticalmodels, and less costly than experimental testing. The Discrete Element Method(DEM) was specifically developed for granular materials such as soils and can beused to model a vibrating tillage tool for its design and optimization. The goalwas thus to evaluate the ability of DEM to model a vibratory subsoiler and toinvestigate the cause of the draft force reduction.The DEM model was evaluated against data obtained from field testing donewith a full scale single tine vibratory subsoiler. Soil testing was also done formaterial characterization and for the calibration of DEM material properties.The subsoiler was simulated using a commercial code, PFC3D. The effect onthe simulation results of particle diameter, different bonding models and dampingmodels was investigated. The final simulations were evaluated against the experimentalresults in terms of the draft force and material behaviour. The cause ofthe draft force reduction due to vibration was also investigated with the aid of theDEM model.From the results it was concluded that DEM is able to model the vibratorysubsoiler for its design and optimization. The DEM model also provided valuableinsight into the cause of the draft force reduction such as the increased peak stressesdue to vibration and the increase in particle kinetic energy.

[发布机构] Stellenbosch University