LAUSR

The force components of a soil-engaging machine are required for selecting tractor power and for the proper design of the machine. The finite element method (FEM) was combined with regression analyses to develop models for the force components of a mouldboard plough as functions of soil physical properties (moisture content and dry bulk density), ploughing speed and ploughing depth. Using a 3D-FEM model of a cylindrical mouldboard–soil interaction, force components (i.e. longitudinal, lateral and vertical) of the mouldboard plough were simulated for a range of moisture content (0.03–0.22 m3 m−3) and dry bulk density (1.15–1.77 Mg m−3) of a sandy-loam soil. A total of 189 simulations were performed with varying depth and speed between 0.1 to 0.25 m and 0.9–2.25 m s−1, respectively, for each combination of soil property. Regression models were developed for the force components e.g. for draught, a model with R2 = 0.82 and RMSE = 0.78 kN was obtained. For validation of the draught model, the FEM-simulated draught was compared with experimental field measurements and the draught calculated by the analytical model of Godwin, O’Dogherty, Saunders, & Balafoutis, (2007). The measured draught was found to be within 3–9.5% and 4–17% larger than FEM-simulated and analytical calculated draught, respectively. Thus, it can be concluded that the FEM-statistical models developed could be simple and useful tools for estimating the force components of a mouldboard plough under combinations of soil physical properties and operating parameters.