Discrete element method optimisation of a scraper to remove soil from ridges formed to cold-proof grapevines

Abstract

A scraper is the most commonly used tool for removing soil from ridges used to cold-proof vines grown in northern China. It can have different complex shapes and its structure and working parameters are vital for effectively removal soil and saving energy. In this study, the interaction between the scraper and the soil was simulated using discrete element method (DEM) simulation, and a calibrated DEM model was developed to simulate soil removal of the scraper. The scraper with different profiles (straight-line, arc, and parabola), different entry angle (δ) and different wing opening angle (θ) were simulated and analysed at various forward speeds (v) in DEM model. The draught force and bilateral soil throw width of the scraper were used to evaluate the effect of soil removal. The DEM model was verified by field experiment, and the draught force and bilateral soil throw width in DEM simulation were compared with the field experiment and the relative errors were 5.97% and 2.88%, respectively. This shows that the DEM model can accurately simulate and optimise the scraper. In order to achieve the best soil removal effect, that is to minimise the draught force and to maximise the bilateral soil throw width, the scraper with arc profile was selected and the optimised values of δ, θ and v were 60°, 86° and 0.6 m s−1, respectively. The corresponding optimal values of draught force and bilateral soil throw width were 58.55 N and 1223 mm, respectively, and based on the optimized parameters, the optimisation results were verified.