柔性脱粒齿杆与谷物含摩擦打击动力学模型  

Frictional impact dynamics model of threshing process between flexible teeth and grains

作　　者：钱震杰 金诚谦 袁文胜 倪有亮 张光跃 QIAN Zhen-jie;JIN Cheng-qian;YUAN Wen-sheng;NI You-liang;ZHANG Guang-yue(Nanjing Institute of A gricultural Mechanization,Ministry of Agriculture and Rural Affairs,Nanjing 210014,China)

机构地区：[1]农业农村部南京农业机械化研究所,南京210014

出　　处：《吉林大学学报（工学版）》2021年第3期1121-1130,共10页Journal of Jilin University:Engineering and Technology Edition

基　　金：国家自然科学基金青年基金项目(11602120);国家重点研发计划项目(2016YFD0702003);中央高校基本科研业务费专项资金项目(S201812);现代农业产业技术体系建设专项资金项目(CARS-04-PS26)。

摘　　要：针对联合收割机脱粒过程,结合Lagrange乘子法和多体系统刚柔耦合理论,建立和分析了脱粒齿杆与谷物含摩擦接触的互作用机理的打击动力学模型。将脱粒过程描述为打击初始时刻、黏滞接触、滑移接触等阶段,引入增减接触约束法,分阶段建立动力学方程,并给出了碰撞搜索算法和状态切换准则。通过自行编制的C语言仿真程序,计算获得了不同脱粒滚筒转速下,脱粒齿打击谷物时的法向打击力、切向揉搓力以及在打击过程中脱粒齿的振动和变形。对纵轴流柔性脱粒滚筒模型进行了EDEM软件仿真和试验验证,结果表明:与普通刚性脱粒齿相比,柔性齿在打击中形成一系列持续的法向打击力和多次反复的微小切向揉搓力,有助于提高脱净率和降低籽粒损伤率。The multiple frictional contact dynamics of the flexible threshing tooth against grains were presented using an addition-deletion constraints approach.During threshing,the grains undergo impacts and rubbing as they fall from straw to become free particles,thus,they experience a serious of frictional collisions and mutual sliding with tooth.An accurate model of a flexible threshing tooth was established on the basis of high-order rigid-flexible coupling theory.The threshing process was characterized by load-off,multiple sliding-stick collisions and separation.An addition-deletion constraints approach was used to solve the dynamic equations for separation,initial contact,stick,and slip.The contact detection and prediction were made with every integral step.Once contact-pairs between threshing tooth and grains were detected through searching algorithm,the multiple contact constrains as well as constrains equations were activated.Corresponding computational strategy software in the C programming language was developed with explicit solution method.It can obtain the vibration and deformation of threshing teeth,as well as the normal impact force and the tangential stick-slip kneading force of threshing teeth against grains.EDEM software simulation and experimental verification were carried out on the longitudinal flow flexible threshing drum model.The results show that the flexible tooth exerts a less impactful kneading force than the rigid pole tooth on cracked grains or seed,thereby reducing the rate of grain damage,and is thus favorable for increasing the combined benefits to paddy production.

关 键 词：农业工程 刚柔耦合理论 LAGRANGE乘子法 柔性脱粒齿 黏滞-滑移 

分 类 号：S225.3[农业科学—农业机械化工程]