基于单轴密闭压缩试验的草炭离散元参数标定  

Calibration of Peat Discrete Element Parameters Based on Uniaxial Closed Compression Test

作　　者：王斌斌 何智 丁辛亭 郝伟 杨珍 崔永杰[1,2] WANG Binbin;HE Zhi;DING Xinting;HAO Wei;YANG Zhen;CUI Yongjie(College of Mechanical and Electronic Engineering,Northwest A&F University,Yangling,Shaanxi 712100,China;Key Laboratory of Agricultural Internet of Things,Ministry of Agriculture and Rural Affairs,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学机械与电子工程学院,陕西杨凌712100 [2]农业农村部农业物联网重点实验室,陕西杨凌712100

出　　处：《农业机械学报》2024年第5期87-97,共11页Transactions of the Chinese Society for Agricultural Machinery

基　　金：陕西省重点研发计划项目(2019ZDLNY02-04)。

摘　　要：为了提升穴盘播种过程中草炭装盘、压穴、覆料的仿真准确性,基于草炭的物料特性,选择Edinburgh Elasto-Plastic Adhesion(EEPA)模型在EDEM软件中建立草炭离散元仿真模型,通过单轴密闭压缩和虚拟仿真试验对草炭参数进行标定。通过物理试验测得草炭密度、粒径分布和接触参数,应用Plackett-Burman Design和最陡爬坡试验设计显著性分析试验,发现草炭间恢复系数、静摩擦因数、草炭切向刚度因子和剪切模量影响显著。应用Central Composite Design试验建立响应值与4个显著性参数的二次多项式回归模型,以单轴密闭压缩20%、50%轴向应变对应的轴向压力3.83、91.45 N为目标值对显著性参数进行寻优,得到最优组合为:草炭间恢复系数0.202、草炭间静摩擦因数0.595、切向刚度因子0.667、草炭剪切模量0.613 MPa。最后将该参数组合下的仿真值与实测值进行对比验证,在轴向应变范围20%~50%内实测值与仿真值的平均误差约为8.08%。相对误差在轴向应变40%左右达到最大值,为15.34%。结果表明基于响应面法标定的EEPA模型参数可用于离散元仿真研究。To enhance the accuracy of simulating charcoal loading,hole pressing,and overlaying in the hole tray seeding process,based on the material properties of charcoal,the Edinburgh Elasto Plastic Adhesion(EEPA)model was selected to establish a discrete element simulation model of charcoal in EDEM software.The peat parameters were calibrated through shaft-closed compression and virtual simulation tests,while the density,particle size distribution,and contact parameters of peat were measured through physical experiments.Significance analysis experiments were designed by using Plackett Burman Design and the steepest climbing test to determine the restitution coefficient,static friction coefficient,tangential stiffness factor,and shear of peat,with modulus having a significant effect.A quadratic polynomial regression model was established between the response value and four significant parameters using the central composite design test.The axial pressures of 3.83 N and 91.45 N corresponding to the uniaxial closed compression of 20% and 50% axial strain were used as target values for testing the significant parameters.After optimization,the optimal combination was determined to be a recovery coefficient of 0.202 between peat plants,a static friction coefficient of 0.595 between peat plants,a tangential stiffness factor of 0.667,and a peat shear modulus of 0.613 MPa.Finally,the simulated values and the measured values under this parameter combination were compared and verified.The average error between the measured values and the simulated values in the axial strain range of 20% to 50% was approximately 8.08%,with the relative error reaching the maximum value of 15.34% at about 40% of axial strain.These results demonstrated that the EEPA model parameters calibrated based on the response surface method can be used for discrete element simulation research.

关 键 词：草炭 单轴密闭压缩 离散元 轴向压力 参数标定 

分 类 号：S565.9[农业科学—作物学] TP181[自动化与计算机技术—控制理论与控制工程]