| 土壤-水稻前茬离散元仿真参数标定及其旋耕轨迹分析 |
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| 引用本文： | 赵智豪,吴明亮,谢双鹏,罗海峰,黎鹏程,曾熠,蒋啸虎.土壤-水稻前茬离散元仿真参数标定及其旋耕轨迹分析[J].农业工程学报,2024,40(7):72-82. |
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| 作者姓名： | 赵智豪 吴明亮 谢双鹏 罗海峰 黎鹏程 曾熠 蒋啸虎 |
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| 作者单位： | 湖南农业大学机电工程学院，长沙 410128;湖南农业大学机电工程学院，长沙 410128;湖南省现代农业装备工程技术研究中心，长沙 410128 |
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| 基金项目： | 国家重点研发计划项目(2022YFD2300103) ；油菜垄作窄垄深沟成形原理及装置参数优化研究（S2021JJMSXM2203）；南方丘陵山区油麦兼用联合播种机（NK202216020101)；土壤表面微型貌对南方红黄壤提质机理及其工作部件研究（2022JJ40168） |
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| 摘 要： | 在进行稻油轮作区域水稻收获后旋耕作业中的前茬运动、受力仿真分析时，由于缺乏可靠的离散元仿真参数难以准确计算土壤-水稻前茬运动规律和相互间受力。该研究采用EDEM软件对土壤-水稻前茬混合物内部各物质的物理与接触参数进行离散元仿真标定。首先测定了土壤-水稻前茬混合物内各物质物理与相互间接触参数，以堆积角作为评价指标，利用仿真试验分析进行了显著因素筛选、最优水平取值范围确定及二阶回归模型下最佳参数寻优对参数进行了标定，得到土壤-水稻前茬混合物模型极显著参数的最优组合为土壤-土壤恢复系数0.407、土壤-土壤动摩擦系数0.123、土壤-水稻前茬静摩擦系数0.596、土壤表面能1.860 J，此时与试验堆积角误差为0.58%。并进行了土壤-水稻前茬间的直剪试验与仿真，得到了稳定后不同垂直应力下试验与仿真的直剪切应力误差分别为：5.4%（50 kPa），4.1%（100 kPa），3.1%（150 kPa）。最后在最优参数组合下，开展了基于MBD-DEM的旋耕土壤-水稻前茬轨迹分析试验，分析得到前茬跟随旋耕刀及直接被掩埋两种埋覆场景，仿真与土槽试验轨迹的Spearman秩相关系数分别为0.91,0.84，验证了仿真模型标定参数的准确性。研究结果可为水稻前茬旋耕轨迹调控过程的离散元仿真分析提供可靠的接触参数。
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| 关 键 词： | 离散元 直剪试验 堆积角 水稻前茬 接触参数 旋耕轨迹 |
| 收稿时间： | 2023/9/12 0:00:00 |
| 修稿时间： | 2023/12/16 0:00:00 |
Parameter calibration for the discrete element simulation of soil-preceding rice stubble and its rotary tillage trajectory |
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| ZHAO Zhihao,WU Mingliang,XIE Shuangpeng,LUO Haifeng,LI Pengcheng,ZENG Yi,JIANG Xiaohu.Parameter calibration for the discrete element simulation of soil-preceding rice stubble and its rotary tillage trajectory[J].Transactions of the Chinese Society of Agricultural Engineering,2024,40(7):72-82. |
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| Authors: | ZHAO Zhihao WU Mingliang XIE Shuangpeng LUO Haifeng LI Pengcheng ZENG Yi JIANG Xiaohu |
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| Abstract: | Due to the lack of reliable discrete element simulation parameters, the motion pattern and mutual force of soil-preceding rice stubble cann''t be accurately calculated during rotary tillage after rice harvest in rice-oilseed rape rotation area. The EDEM software was used in this study to calibrate the physical and contact parameters of each substance within the soil-preceding rice stubble mixture by discrete element simulation. A series of physical experiments were carried out to determine the physical and mutual contact parameters of each substance within the soil-preceding rice stubble mixture, including density, modulus of elasticity, Poisson''s ratio, static friction parameter, rolling friction parameter, and collision recovery coefficient. Taking the accumulation angle as the evaluation index, the Plackett-Burman experiment was used to screen the significant factors, and the range of factors was further optimized by the steepest-climbing experiment, and the Box-Behnken experiment was further carried out within the optimized range, to observe the effects of the factors and interactions on the model, and then a second-order regression model was obtained to search for the optimal parameters and to complete the model calibration. The optimal parameter combination of the most significant parameters of the soil-preceding rice stubble model were soil-soil recovery coefficient 0.407 , soil-soil kinetic friction coefficient 0.123, soil-preceding rice stubble static friction coefficient 0.596, and the soil surface energy 1.860 J, The error of actual accumulation angle was 0.58% under the optimal parameter combination. Direct shear experiments and simulations for the soil-preceding rice stubble were carried out, in which a scenario of preceding rice stubble crumb embedded into the soil consistent with the physical experiment was observed in the simulation. The shear stress errors of the simulated and experimented direct shear stresses at different vertical loadings after vertical stress stabilization were obtained as 5.4% (50 kPa), 4.1% (100 kPa), and 3.1% (150 kPa), respectively. The reasons for the errors under different vertical stresses were analyzed from both the model itself and the experiments, and the accuracy of the simulation model''s contact stresses was verified. Under the optimal parameter combination, the MBD-DEM-based rotary soil-preceding rice stubble trajectory analysis experiment was carried out, and two soil-preceding rice stubble burial scenarios were summarized, in which it was observed that the rice preceding stubble would fall in the opposite direction to the forward direction of the rotary tillage and be squeezed by the subsequent knives to the bottom of the soil furrow formed by the soil disturbed and by the previous rotary knives, and finally buried by the soil thrown up by the subsequent rotary tillage, and that the soil-preceding rice stubble would slowly break away from the rotary tillage trajectory to do curved motion, and would be buried by the airborne soil-preceding rice stubble due to the eccentricity of the center of mass of the soil-preceding rice stubble. Because the center of mass of the soil-preceding rice stubble in the air is biased toward the root end of the rotation of the two scenarios. By calculating the Spearman''s rank correlation coefficients (0.91,0.84) between the simulation and the soil groove experiment trajectory, the accuracy of the contact motion of the simulation model was verified, and reliable contact parameters were provided for the discrete element simulation analysis of the preceding rice stubble rotary tillage trajectory regulation process. |
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| Keywords: | discrete element method direct shear experiment accumulation angle preceding rice stubble contact parameters rotary tillage trajectory |
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