摘要
针对胡麻联合收获过程中茎秆位姿变化与运动特性等关键环节离散元研究缺乏柔性模型和接触参数的问题,本文以胡麻根部茎秆、中部茎秆、颈部茎秆为研究对象,以其本征参数为研究基础,计算得胡麻茎秆各部建模参数,采用离散元法bonding模型构建胡麻茎秆柔性模型,并以胡麻茎秆各部本征参数、接触参数试验值为水平值,通过Plackett Burman试验和Central Composite试验确定胡麻茎秆之间、茎秆与收获装备之间的接触参数,通过胡麻茎秆剪切试验与堆积角试验验证模型可靠性。结果表明:胡麻植株离散元柔性模型参数中法向刚度K_(n)为1.13×10^(9)N/m^(3),切向刚度K_(s)为5.6×10^(8)N/m^(3),法向临界应力σ为6.67 MPa,切向临界应力γ为8.5 MPa,粘结半径R_(j)为0.25 mm;胡麻茎秆收获装备间恢复系数、静摩擦因数、滚动摩擦因数最优值分别为0.33、0.28、0.14,胡麻茎秆胡麻茎秆间恢复系数、静摩擦因数、滚动摩擦因数最优值分别为0.3、0.508、0.033;剪切试验中胡麻茎秆根部、中部、颈部剪切最大载荷与仿真结果相对误差分别为1.67%、3.09%、5.44%,堆积角试验中胡麻茎秆平均堆积角与仿真结果相对误差为0.31%,误差较小。胡麻茎秆柔性模型与接触参数和实际情况较为相符,可表征胡麻茎秆物理特性,为胡麻茎秆离散元仿真提供参考。
Flax stems contain a large amount of cellulose and have strong toughness.The discrete element rigid model is challenging to express the physical and kinematic characteristics of flax accurately stems in the process of joint harvesting,resulting in the lack of flexible model and contact parameters in the dynamic process of communal harvesting and difficult to micro study.In order to solve this problem,the root,middle,and neck stems of flax were taken as the research objects.The modeling parameters of flax stems were calculated based on the intrinsic parameters.The bonding modeling method of the discrete element method was used to construct the flexible model of flax stems,and the intrinsic parameters and contact parameters of flax stems were set as high and low levels.Plackett-Burman and Central-Composite tests were used to determine the contact parameters between flax stems and harvesting equipment.The flax stem shear test and stacking angle test were used to verify the model’s reliability.The results showed that the normal stiffness K_(n)=1.13×10^(9)N/m^(3),and tangential stiffness K_(s)=5.6×10^(8)N/m^(3)in the flax flexible model parameters.Normal critical stressσ=6.67 MPa,tangential acute stressγ=8.5 MPa,bond radius R_(j)=0.25 mm.The optimal values of recovery coefficient,static friction coefficient,and dynamic friction coefficient between flax culm-steel parts were 0.33,0.28 and 0.14,respectively.The optimal values of recovery coefficient,static friction coefficient,and dynamic friction coefficient between flax stems-flax stems were 0.3,0.508,and 0.033,respectively.In the shear test,the relative errors between the maximum shear load and the simulation results were 1.67%,3.09%and 5.44%,respectively.In the stacking angle test,the relative error between the average stacking angle of the stem and the simulation results was 0.31%.The flexible modulus of flax stem was consistent with the contact parameters and the actual situation.The physical properties of flax stem can be characterized.The research result can provide some reference for discrete element simulation of flax stem.
作者
史瑞杰
戴飞
赵武云
张锋伟
石林榕
郭军海
SHI Ruijie;DAI Fei;ZHAO Wuyun;ZHANG Fengwei;SHI Linrong;GUO Junhai(College of Mechanical and Electrical Engineering,Gansu Agricultural University,Lanzhou 730070,China)
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2022年第10期146-155,共10页
Transactions of the Chinese Society for Agricultural Machinery
基金
财政部和农业农村部:国家现代农业产业技术体系项目(CARS-14-1-28)
甘肃省重点研发计划项目(20YF3WA019)
甘肃省科技计划重大专项(21ZD4NA022-05)
甘肃农业大学青年导师扶持基金项目(GAU-QDFC-2021-08)
甘肃省教育厅优秀研究生“创新之星”项目(2021CXZX-362)
关键词
胡麻茎秆
离散元法
柔性模型
接触参数
试验验证
flax stem
discrete element method
flexible model
contact parameters
test verification
作者简介
史瑞杰(1993—),男,博士生,主要从事北方旱区特色作物机械化收获技术与装备研究,E-mail:aete_fcb@163.com;通信作者:赵武云(1966—),男,教授,博士生导师,主要从事北方旱区作物生产装备工程研究,E-mail:zhaowy@gsau.edu.cn
