A 3D Finite Element Simulation Analysis of the Soil Forces Acting on a Rotary Blade

Proper prediction of tillage force is difficult, inconvenient, and time-consuming in field work since many external factors should be taken into consideration. The need for a sound modeling technique to predict tillage force is the motivation for the present work. The finite element method (FEM) is a proven and effective approach for modeling soil-tool interaction. In this study, 3D dynamic simulation models using FEM of a conventional rotary blade were established to predict the effects of rotational speed and direction. The soil was modeled as an elastic-plastic material with elastic parameters such as Young’s modulus, Poisson’s ratio, and the Drucker-Prager criterion, which were obtained from triaxial tests. A general contact algorithm was used to simulate the interaction between the rotary blade and the soil. Two rotational directions and three rotational speeds were analyzed by the finite element model and experimentally verified in an indoor soil bin. A relatively good general correlation was obtained between the finite element simulation and the experimental results. The simulation and experimental results both indicated that applied torque on the rotor shaft increases with rotary speed, and the torque of up-cut rotary tillage is larger than that of down-cut tillage.