摘要
研究根土复合体铲切过程可以获得铲切力并优化铲切结构等参数。为准确仿真根系的切割过程,利用离散元法建立了颗粒粘结的蔬菜根简化模型。以成熟期的菠菜主根为试验材料,利用WDW-5E型微机控制电子式万能试验机进行菠菜主根的物理特性试验,得到菠菜主根的力学性能参数,即峰值剪切力为31.2N、轴向峰值压缩力为113.8N。结合离散元颗粒接触模型本构方程,得出相关粘结参数值,即法向刚度系数为5.7×10^(6)N/m、切向刚度系数为3.6×10^(6)N/m,临界法向应力为1.95 MPa,临界切向应力为4.2MPa,粘结半径为0.8mm。利用上述参数建立了根系离散元粘结模型,进行虚拟试验与实际物理试验对比分析,结果表明:两者在根系剪切力的变化趋势和压缩表观特征参数上具有一致性。因此,证明本文方法可以应用于菠菜根模型建立,对根土复合模型的建立及铲刀的优化设计等具有一定的参考意义。
Study the cutting process of root-soil complex models can obtain parameters such as cutting force and optimize cutting structure. In order to simulate the root cutting process accurately, this paper uses the discrete element method to establish a simplified model of vegetable root. The spinach roots in the mature period are used as the experimental materials. The physical properties of spinach main root were tested by WDW-5 E microcomputer controlled electronic universal testing machine. The mechanical performance parameters of the spinach roots are obtained: the peak shear force is 31.2 N, and the axial peak compression force is 113.8 N. Combined with the constitutive equation of the discrete element particle contact model, the relevant bonding parameters are obtained: the normal stiffness coefficient is 5.7×10^(6)N/m, the tangential stiffness coefficient is 3.6×10^(6) N/m, the critical normal stress is 1.95 MPa, the critical tangential stress is 4.2 MPa, and the bonding radius is 0.8 mm. The discrete element model is established and bonded. The virtual test is carried out on that and compared with the actual physical test, and the results show that the DEM can be applied to the establishment of spinach root model. This study has certain reference significance for the establishment of root-soil composite model and the optimal design of blade.
作者
李金光
刘雪美
邹亮亮
尹然光
杨坤
苑进
Li Jinguang;Liu Xuemei;Zou Liangliang;Yin Ranguang;Yang Kun;Yuan Jin(College of Mechanical and Electrical Engineering,Shandong Agricultural University,Tai’an 271018,China;Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment,Tai’an271018,China)
出处
《农机化研究》
北大核心
2021年第8期181-185,191,共6页
Journal of Agricultural Mechanization Research
基金
国家自然科学基金项目(51675317)
国家重点研发计划项目(2017YFD0701103-3)。
关键词
叶菜采收
物理特性试验
离散元
vegetable harvesting
physical property test
discrete element method
