| 冰草种子物性参数测定与离散元仿真参数标定 |
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| 引用本文： | 侯占峰,戴念祖,陈智,仇义,张曦文.冰草种子物性参数测定与离散元仿真参数标定[J].农业工程学报,2020,36(24):46-54. |
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| 作者姓名： | 侯占峰 戴念祖 陈智 仇义 张曦文 |
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| 作者单位： | 内蒙古农业大学机电工程学院,呼和浩特 010018;扬州工业职业技术学院交通工程学院,扬州 225127 |
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| 基金项目： | 国家自然科学基金资助项目（41661058）；内蒙古自然科学基金（2018MS05023） |
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| 摘 要： | 为了提高冰草种子丸化包衣过程离散元仿真模拟试验所用参数的准确度，该研究通过物理试验和仿真试验相结合的方法对仿真参数进行标定。首先，采用物理试验的方法测定冰草种子的基本物性参数（外形尺寸、千粒重、密度、含水率、泊松比、弹性模量和剪切模量）和接触参数（静摩擦系数、滚动摩擦系数和碰撞恢复系数），参考物理试验测定结果选择仿真试验参数取值范围，采用Plackett-Burman试验对仿真参数进行显著性筛选，筛选试验结果表明：冰草种子-冰草种子静摩擦系数、滚动摩擦系数、碰撞恢复系数对仿真试验休止角有显著性影响。进一步通过最陡爬坡试验确定3个显著性参数最优取值范围，并根据Box-Behnken设计试验得到显著性参数与休止角的二阶回归模型，以物理试验实测的休止角30.54°为优化目标值获得最优参数组合：冰草种子-冰草种子静摩擦系数为0.57、冰草种子-冰草种子滚动摩擦系数为0.74、冰草种子-冰草种子碰撞恢复系数为0.54。最后对物理试验休止角和仿真试验休止角进行双样本T检验得出P>0.05，结果表明仿真得到的休止角与物理试验值无显著性差异，且最优参数组合下仿真试验休止角结果30.86°与物理试验休止角结果30.54°的相对误差为1.037%，进一步验证了仿真试验的可靠性。研究结果表明标定所得的最优参数可用于冰草种子丸化包衣过程的离散元仿真试验。
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| 关 键 词： | 参数 休止角 离散元 优化 冰草种子 |
| 收稿时间： | 2020/8/20 0:00:00 |
| 修稿时间： | 2020/12/2 0:00:00 |
Measurement and calibration of physical property parameters for Agropyron seeds in a discrete element simulation |
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| Hou Zhanfeng,Dai Nianzu,Chen Zhi,Qiu Yi,Zhang Xiwen.Measurement and calibration of physical property parameters for Agropyron seeds in a discrete element simulation[J].Transactions of the Chinese Society of Agricultural Engineering,2020,36(24):46-54. |
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| Authors: | Hou Zhanfeng Dai Nianzu Chen Zhi Qiu Yi Zhang Xiwen |
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| Institution: | 1.College of Mechanical and Electrical Engineering, Inner Mongolia Agricultural University, Hohhot 010018;2.Yangzhou Polytechnic Institute, College of Transportation Engineering, Yangzhou 225127, China |
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| Abstract: | Abstract: Agropyron is a perennial xerophytic grass of the gramineae, and it is one of the most important grass species in arid and semi-arid areas. Because of its characteristics of drought resistance, cold tolerance and grazing tolerance, it is widely used in the process of reseeding in grazing areas and spray sowing in artificial grasslands on dry land. In addition, the roots of wheatgrass are whisker-like, densely growing and sand-gathering. It is also a plant of good soil and water conservation and wind-proof and sand-fixing.In the simulation analysis of discrete element method for the process of pelleting and coating of Agropyron seeds, the accuracy of simulation parameters is very important, it is of great significance to improve the accuracy of the simulation parameters. The method of combining physical test and simulation test was used to calibrate the simulation parameters used in EDEM software for the process of pelleting and coating of Agropyron seeds in this study. The basic physical parameters of Agropyron seeds (dimensions, thousand-grain weight, density, moisture content, Poisson''s ratio, elastic modulus and shear modulus) and contact parameters (static friction coefficient, rolling friction coefficient and collision restitution coefficient) are determined through physical test, the measurement result of physical test indicated that the collision restitution coefficient of Agropyron seed-Agropyron seed ranged from 0.45 to 0.65, static friction coefficient of Agropyron seed-Agropyron seed ranged from 0.50 to 0.70, and rolling friction coefficient of Agropyron seed-Agropyron seed ranged from 0.60 to 0.90, the collision restitution coefficient of Agropyron seed-steel plate ranged from 0.40 to 0.60, static friction coefficient of Agropyron seed-steel plate ranged from 0.20 to 0.40, and rolling friction coefficient of Agropyron seed-steel plate ranged from 0.30 to 0.60 respectively. Taking the physical parameters determined by the physical test as the basis for the selection of simulation test parameters,the Plackett-Burman was carried out significantly screen the parameters of simulation test. The results show that: static friction coefficient of Agropyron seed-Agropyron seed, rolling friction coefficient Agropyron seed-Agropyron seed and the collision restitution coefficient Agropyron seed-Agropyron seed have a significant effect on the angle of repose in the simulation experiment. The steepest climbing test is further used to determine the optimal value ranges of the three significance parameters. Through the Box-Behnken test, the second-order regression equation of the repose angle and the saliency parameter is established, and the optimal value of the repose angle(30.54°) is used to optimize the solution, and the best simulation parameters is obtained: the collision restitution coefficient of Agropyron seed-Agropyron seed is 0.54, static friction coefficient of Agropy ron seed-Agropyron seed is 0.57, and the rolling friction coefficient of Agropyron seed-Agropyron seed is 0.74. Finally, the two-sample T test of the repose angle of physical test and simulation test shows that P>0.05. The results show that the angle of repose obtained by simulation is not significantly different from the physical test value, the relative error of the simulation test result(30.86°) under the optimal parameter combination and the repose angle of physical test result(30.54) is 1.037%, which further verifies the reliability of the simulation test. The research results show that the optimized parameters obtained by calibration can be used in the discrete element simulation experiment of the pelletizing and coating process of Agropyron seeds. |
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| Keywords: | Agropyron seed parameter calibration repose angle discrete element optimization |
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