摘要
【目的】针对解决水稻清选物料堵塞离散元建模缺乏准确模型问题,为提高水稻植株离散元建模及仿真研究中所用参数的准确度,【方法】以带有叶鞘包裹的水稻茎秆为研究对象,通过斜面试验测定稻秆与不锈钢板之间的静摩擦系数和滚动摩擦系数,接着基于离散元HBP仿真模型,先后通过堆积角试验和三点弯曲试验,以茎秆泊松比v、茎秆剪切模量Gb、茎秆-茎秆碰撞恢复系数e、茎秆-茎秆静摩擦系数us、茎秆-茎秆滚动摩擦系数ut、茎秆-茎秆粘结半径R_(b)、茎秆-茎秆切向粘结刚度ktb和茎秆-茎秆法向粘结刚度k_(nb)为试验因素,以茎秆堆积角θ和茎秆弹性模量E_(b)为试验因素评价指标,综合采用Plackett-Burman、Central-Composite和Box-Behnken试验方法,对水稻茎秆接触参数和粘结参数进行离散元仿真标定。【结果】Plackett-Burman试验结果表明:us与ut(P<0.01)对θ影响极显著,ut与ktb(0.01<P<0.05)对E_(b)影响显著,R_(b)与k_(nb)(P<0.01)对E_(b)影响极显著,v、Gb与e对θ和E_(b)影响均不显著;Central-Composite试验和Box-Behnken试验得到最佳参数组合为:茎秆-茎秆静摩擦系数为0.35、茎秆-茎秆滚动摩擦系数为0.016,茎秆-茎秆粘结半径为2.331 mm、茎秆-茎秆法向粘结刚度4.71×10^(9)N/m^(3)、茎秆-茎秆切向粘结刚度3.67×10^(9)N/m^(3)。【结论】最后将最佳参数组合下的仿真试验结果与物理试验结果进行对比验证,结果表明,仿真试验茎秆堆积角与物理试验茎秆堆积角的相对误差为1.26%,仿真试验茎秆弹性模量与物理试验茎秆弹性模量的相对误差为0.72%,通过SPSS软件对试验结果进行T检验发现无显著性差异(P>0.05),表明基于HBP仿真模型所标定的接触参数与粘结参数结果准确,可用于水稻植株离散元建模,为离散元仿真研究提供参数依据。
[Objective]Due to the lack of accurate model in discrete element simulation of material motion blockage in rice harvesting process,this study aims to improve the accuracy of parameters used in rice plant discrete element modeling and simulation.[Methods]This study selected the rice stalk wrapped with leaf sheath as the research object,the static friction coefficient and rolling friction coefficient between rice stalk and stainless steel plate were measured by inclined plane test.Based on the discrete element Hertz-Mindlin with bonding particle simulation model,the stacking angle tests and three-point bending tests were implemented by takeing the stalk Poisson’s ratio v,the stalk shear modulus G_(b),the stalk-stalk recovery coefficient e,the stalk-stalk static friction coefficient us,the stalk-stalk rolling friction coefficient ut the stalk-stalk bonding radius R_(b),the stalkstalk tangential bonding stiffness ktb and stalk-stalk normal bonding stiffness k_(nb)as the experimental factorsand the stalk stacking angleθand the stalk elastic modulus E_(b)as the evaluation index of test factors.In addition,this study adopted Plackett-Burman,Central-Composite and Box-Behnken test methods,the contact parameters and bonding parameters of rice straw were calibrated by discrete element simulation.[Results]The PlackettBurman test results showed that:the influence of the stalk-stalk static friction coefficient us and the stalk-stalk rolling friction coefficient ut(P<0.01)affecting the stalk stacking angleθwas significant,the stalk-stalk rolling friction coefficient ut and the stalk-stalk tangential bonding stiffness k_(tb)(0.01<P<0.05)had a significant influence on the stalk elastic modulus E_(b),the stalk-stalk bonding radius Rb R_(b)and the stalk-stalk normal bonding stiffness k_(nb)(P<0.01)had a significant effect on the stalk elastic modulus E_(b),the stalk Poisson’s ratio v,the stalk shear modulus G_(b)and the stalk-stalk recovery coefficient e on the stalk stacking angleθand the stalk elastic modulus E_(b)had no s
作者
侯杰
谢方平
王修善
刘大为
陈志刚
HOU Jie;XIE Fangping;WANG Xiushan;LIU Dawei;CHEN Zhigang(College of Mechanical and Electrical Engineering,Hunan Agricultural University,Changsha 410128,China;Hunan Provincial Key Laboratory of Intelligent Agricultural Machinery Equipment,Changsha 410128,China)
出处
《江西农业大学学报》
CAS
CSCD
北大核心
2022年第3期747-758,共12页
Acta Agriculturae Universitatis Jiangxiensis
基金
湖南省自然科学基金项目(2021JJ30333)。
关键词
水稻茎秆
离散元
堆积角
弹性模量
参数标定
rice stalk
discrete element
stacking angle
elastic modulus
parameter calibration
