Draught force prediction from soil relative density and relative water content for a non-winged chisel blade using finite element modelling

Abstract

This study aims to develop a model for prediction of the draught force of a new narrow non-winged chisel blade as a function of tillage depth (d), forward speed (v), soil relative water content (wrel), and soil relative density (ρrel) based on combination of statistical and finite element (FE) models. The soil-chisel blade interaction was simulated for various combinations of relative density and relative water content of a sandy loam soil at three levels of forward speed (i.e., 2, 3, and 5 km h−1) and three levels of tillage depths (i.e., 0.15, 0.2, and 0.25 m) using finite element method. The draught force of each simulation was obtained and used to develop a statistical model. A simple model with an adjusted coefficient of determination (Radj2) of 0.81 and the root mean square error (RMSE) of 0.3 kN was proposed for draught force. This model was tested for a set of experimental data obtained in a clay loam soil. The fitted regression line to the data showed that the predicted draught forces lie within bounds of ±6% of the measured values with a coefficient of determination of 0.96. In general, the results of this study showed that using relative density and relative water content, a prediction model could be developed for draught force to work across soil textures. Further studies in a wider range of soil textures are suggested to evaluate the model for the tillage tool.