Study the effect of tool geometry and operational conditions on mouldboard plough forces and energy requirement: Part 1. Finite element simulation

Abstract

The finite element method (FEM) is commonly used to study the soil cutting process with tillage tools. This paper illustrates the use of FEM to model interaction of a mouldboard plough used in northern Africa. A Drucker–Prager elasto-plastic model was used to simulate the material behavior of a sandy loam soil. The mouldboard was considered as a discrete rigid body with a reference point at the tip, at which the three orthogonal force components (vertical, lateral, and draught) were calculated. The effects of the mouldboard depth of cut, speed of operation, cutting angle (α) and the lifting angle (β) on the tillage forces were investigated in this study. Results showed that draught force increased with a second order polynomial function with depth, whereas the vertical and lateral forces had a linear relationships with depth. Moreover, these forces increased linearly with speed. For the effect of the cutting angles, results showed that the draught force increased linearly with the cutting and the lifting angles. The vertical force decreased linearly with these angles. Whereas, the lateral force decreased with a polynomial trend with the cutting angle and increased linearly with the lifting angle. It was found that the minimal energy consumption can be achieved by a combination of a working depth of 150mm, a speed of 1m/s, low lifting angle (25°), and cutting angle (from 30° to 45°). This combination also resulted in a good soil inversion. It can be concluded that FEM can be used to understand the effect of mouldboard design and operational conditions on tillage forces, energy requirements, and quality of soil inversion.