Optimized mouldboard design for efficient soil inversion using the discrete element method

TL;DR

This work tackles the challenge of improving soil inversion efficiency in mouldboard ploughs while reducing wear and maintaining structural safety. It adopts a DEM-based design workflow to modify a cylindroid MB profile and introduces an inversion index, $I = H_T + H_B + V_T + V_B$, to quantify soil layer displacement. Results show the modified profile boosts inversion index by up to about $32.95\%$ across tested velocities and reduces wear on left/right ploughs by up to $23.7\%$, at the cost of modest increases in draft force and peak stresses, which remain below the $240\,\mathrm{MPa}$ yield of structural steel. The study is simulation-based, and future work will include full-scale experiments and incorporating depth-dependent moisture, soil cohesion, and multi-factor wear models for improved predictive accuracy.

Abstract

The design of a mouldboard (MB) plough is critical for achieving efficient soil inversion, which directly impacts soil aeration, weed control, and overall agricultural productivity. In this work, a design modification of the cylindroid-shaped MB plough is proposed, focusing on optimizing its surface profile to enhance performance. The discrete element method is used to simulate the ploughing process and evaluate the performance of the modified plough profile. The modified plough profile is compared against a previously proposed design to assess its impact on soil inversion efficiency, wear reduction, and stress distribution. A novel methodology is introduced to evaluate the plough's performance in soil inversion. The modified design demonstrates superior soil inversion efficiency, with improvements of up to $32.95\%$ in the inversion index for different velocities. The modified design achieves a notable reduction in wear up to $23.7\%$, compared to the original design. Although a slight increase in stress is observed in the modified design due to higher forces, the induced stresses remain well within the permissible limits for the plough material. Overall, the findings highlight the advantages of the modified plough design, including enhanced soil inversion efficiency and reduced wear, underscoring its potential for improved performance in tillage applications. However, the current study is limited to simulation-based analysis without experimental or field validation. Future work will focus on full-scale physical experiments to validate the simulation outcomes and incorporate additional factors such as depth-dependent moisture, soil cohesion, and multi-factor wear models for improved predictive accuracy.

Figures (14)

• Figure 1: (a) Procedure to design MB plough, and (b) triangular wedge for defining the geometrical parameters of a passive tillage tool, (c) tool surface generation
• Figure 2: (a) Procedure to design MB plough, and (b) Triangular wedge for defining the geometrical parameters of a passive tillage tool
• Figure 3: Soil layer displacement in (a) horizontal, and (b) vertical directions. The working direction of the moldboard plough is into the plane of the paper.
• Figure 4: (a)Width and Layer thickness selection for analysis, and (b) Furrow and ridge formed after ploughing
• Figure 5: 3D view of ploughing simulation