基于离散元与多体动力学的微耕机旋耕刀轴负荷分析

旋耕部件是微耕机的核心部件，其耕作性能的优劣直接影响微耕机的耕作效率和作业质量。以重庆地区典型的旋耕刀辊和土壤为对象，基于离散元和多体动力学理论，设定前进速度为0.2 m·s^-1，转速为110 r·min^-1，耕深为150和200 mm，采用非线性粘弹性塑性接触模型，在EDEM和Recurdyn软件平台上实现了刀辊耕作过程的模拟分析；同时，依托已有的土槽试验平台，测试了相同工况下刀轴的等效扭矩。模拟与试验的对比分析结果表明：同一刀轴上不同刀盘的扭矩变化规律相似，但数值并不一致，整个刀轴所受的等效扭矩不能简单地理解为单个刀盘所受扭矩与刀盘数的乘积；耕作深度为150、200 mm时刀轴等效扭矩的变化规律一致，模拟值与试验值的最大相对误差分别为14.01%、11.49%。研究结果可为探讨旋耕刀与土壤的相互作用，优化微耕机作业性能提供参考。

Load Analysis of Rotary Cutter Shaft for Power Tiller Based on DEM and MBD Theory

Rotary tillage components are the core components of the power tiller, and their quality directly affects the tillage efficiency and work quality of the tiller. The typical rotary cutter shaft and purple soil in Chongqing were taken as the research objects. Based on the discrete element method (DEM) and multi-body dynamics (MBD) theory, the nonlinear visco-elastic plastic contact model (edinburgh elasto-plastic adhesion model, EEPA) was used to analyze the knife roller farming process on the EDEM and Recurdyn software platform under the condition of the forward speed 0.2 m·s^-1, the rotary speed 110 r·min^-1 and the tilling depth 150 or 200 mm. At the same time, the equivalent torque of the cutter shaft was tested on the soil-bin test bed in laboratory developed by our team. The results showed that the torque variation rules of different tool holders on the same cutter shaft were similar, but the values were not consistent. The equivalent torque of the cutter shaft was not simply equal to the torque of a single tool holder timed the number of tool holders. Furthermore, the variation law of the equivalent torque of the cutter shaft was same under different tillage conditions, and the maximum relative error between the simulation results and the experiment results with the tilling depth of 150 and 200 mm were 14.01% and 11.49%, respectively. The results provided the reference for discussion between rotary blades and soil, as well as optimization of the tilling performance of the tiller.