[目的]针对铧式犁在西北旱区作业存在翻耕效果较差、耕作阻力大等问题，基于水平直元线法设计铧式犁犁体曲面，建立导曲线及元线角变化参数方程和西北旱区土壤-犁体耕作阻力模型。[方法]采用离散元软件EDEM，土壤接触模型选择Hertz-Mindlin with JKR接触模型，以元线角、导曲线两端切线夹角和安装角为试验因素，耕作阻力和土壤抛送距离为评价指标，完成Box-Behnken响应面仿真试验并对回归模型进行多目标优化。对优化后最优参数组合下的犁体进行耕作仿真试验，并通过对比优化前与优化后犁体的土壤扰动剖面图和土壤运动云图，进一步分析犁体曲面参数优化的合理性。[结果]当元线角为40。43°、导曲线两端切线夹角为107。01°、安装角为27。16°时，获得最小耕作阻力(2 626。59 N)和较大土壤抛送距离(451。62 mm)。且由土壤扰动分析可知，优化后的犁体在抬升土壤和使土壤产生运动等方面均优于优化前的犁体。[结论]通过田间试验验证优化后的铧式犁的耕深和耕宽稳定性、残茬覆盖率及土垡破碎率等各项性能指标均符合国家标准要求，耕作阻力和土壤抛送距离田间试验结果分别为2 795。43 N和423。57 mm，与仿真试验结果的相对误差分别为6。43%、6。21%，相对误差在合理范围之内，证明铧式犁结构参数设计的合理性。
Simulation analysis and experiment of ploughing process in northwest arid region based on discrete element method
[Objective]In addressing the problems of poor tillage performance and high tillage resistance in the operation of existing moldboard ploughs in the arid regions of Northwest China,a moldboard plough body surface is designed using the horizontal straight element line method.Equations for curve generation,variation of element line angles,and a plough body tillage resistance model are established.[Method]The discrete element software EDEM was used,and the Hertz-Mindlin with JKR contact model was selected as the soil contact model.The Box-Behnken response surface simulation test was completed and the multi-objective optimization of the regression model was carried out by taking the element line angle,the tangent angle at both ends of the guide curve and the installation angle as the test factors,the tillage resistance and the soil throwing distance as the evaluation indexes.Tillage simulations were performed using the optimized parameter combination for the plough body surface,and the rationality of the plough body surface parameter optimization was further analyzed by comparing the sectional view of soil disturbance and soil motion clouds at different stages before and after optimization.[Result]Results reveal that the minimum tillage resistance(2 626.59 N)and a relatively large soil throwing distance(451.62 mm)are achieved with an element line angle of 40.43°,tangential angle at both ends of the guiding curve of 107.01°,and an installation angle of 27.16°.Furthermore,the soil disturbance analysis revealed that the optimized plough body surface performed better than the non-optimized one in terms of lifting the soil and inducing soil motion.[Conclusion]Through field experiments,it is verified that the stability of tillage depth,residual stubble coverage,and the breakage rate of soil of the optimized moldboard plough all meet the requirements of national standards.The field experiment results for tillage resistance and soil throwing distance are 2 795.43 N and 423.57 mm,respectively.The relative errors compared with the simulation experiments results were 6.43%and 6.21%,respectively,falling within a reasonable range.The field experiemtns validate the rationality of the structural parameter design of the moldboard plough.
moldboard ploughdiscrete element methodplough body surfacetillage resistancefield experiment
万方数据
维普
