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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Soil, Water & Air Resources Research » Research » Publications at this Location » Publication #350912

Title: Discrete element modeling of cultivator sweep-to-soil interaction: Worn and hardened edges effects on soil-tool forces and soil flow

item TEKESTE, MEHARI - Iowa State University
item BALVANZ, LORAN - Usm Wear Technologies, Llc
item Hatfield, Jerry
item GHORBANI, SADAF - Iowa State University

Submitted to: Terramechanics Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/8/2018
Publication Date: 4/1/2019
Citation: Tekeste, M.Z, Balvanz, L.R., Hatfield, J.L., Ghorbani, S. 2019. Discrete element modeling of cultivator sweep-to-soil interaction: Worn and hardened edges effects on soil-tool forces and soil flow. Terramechanics Journal. 82:1-11.

Interpretive Summary: Evaluation of tillage equipment and its performance under field conditions is difficult to obtain. Producers often evaluate tillage tools by the length of time before replacement of worn parts on the equipment. There has not been a method available to evaluate worn tillage tools and this study was directed to using a mathematical approach to evaluate how worn versus new tillage sweeps compared under realistic conditions. The comparison was made with the model predictions and observations under field conditions. One of the purposes of this study was to compare a new method of treating sweeps with a different edge technique. It was found that this new method of treating the edge of tillage tools increased their performance under field conditions so they behaved similarly to new tillage tools for a longer period of time compared to an untreated tillage tool. The mathematical model could be used to evaluate tillage tools for their performance without extensive field testing. This information is of value to extension educators, farm machinery manufacturers, and equipment dealers.

Technical Abstract: Simulation of tool-to-soil interaction provides opportunities to accelerate a new equipment design and evaluate performance of tillage tools. Simulation based evaluation of worn tillage tools performance on soil flow has not been done. Discrete Element Modelling (DEM) has a potential to simulate worn tool to soil interaction problems, where worn tools Computer- Aided Design (CAD) can be generated using 3D scanning. The DEM parameters of Hertz-Mendlin with Parallel Bond model were calibrated to match the draft force and the soil failure zone measured from a tool bar moving at 0.22 m/s at a 38 mm cutting depth. The draft force and soil forward failure zone were predicted at 7% and 24% relative errors compared to measured values, respectively. Using the optimized DEM soil model, sweep-to-soil interactions were simulated for three sweeps (new sweep, carbide treated-worn, untreated-worn) and compared to their geometric wear dimensional loss, soil forces and soil flow. Results showed that the carbide treated-worn sweep had similar soil draft force and soil forward failure distance as the new sweep. The untreated-worn sweep showed lower vertical force (less suction), its wing induced a soil failure zone (front and lateral), and it showed poor soil tilth quality compared with the carbide treated worn sweep and the new sweep.