Abstract: In view of the characteristic of china southern hilly soils, especially compacted soil of tea garden, a deep tillage method and a jointed mechanism made up of an up-cut tillage tool and a down-cut tillage tool, is proposed and designed for harden soil deep-tilling with low-power motor. In order to reduce the power of small agricultural machinery dealing with deeply-loosening tillage in hardened soil, a soil reverse-rotary tilling process simulation and a finite element analysis model of soil high-speed cutting are studied by using smoothed particle hydrodynamics finite element method. Accordingly, structural parameters of reverse-rotary tillage tool and the working parameters of reverse-rotary tillage mechanism are studied and optimized by using orthogonal experimental method and FEA numerical simulation technology. The results show that it is perfectly feasible to apply the proposed composite tillage method and jointed mechanism on harden soil deep-tilling with low power motor, and for a soil deep-tilling process, proper structural parameters of tillage tool and working speed can reduce the power consumption of the reverse-rotary tillage mechanism.

Key words: 3D numerical simulation, Contrarotation, Rotavator, Soil mechanics