新疆棉花秸秆离散元仿真参数标定研究

由于棉花秸秆在机械化收获和粉碎加工过程中缺乏准确的仿真模型参数，从而造成在机具设计中仿真效果和实际作业存在较大的差异，在一定程度上限制了棉花秸秆收获以及粉碎装置的设计研究。本文以新疆棉花秸秆作为试验材料，开展仿真分析研究，通过物理试验测定棉花秸秆的本征参数后，利用EDEM软件进行试验仿真，对棉花秸秆进行参数标定。采用堆积角试验和弯曲试验方法，测量出棉花秸秆堆积角和最大破坏载荷分别为28.62°和143.21N。应用Hertz-Mindlin no slip模型和Hertz-Mindlin with bonding模型进行棉花秸秆的堆积角仿真试验和弯曲仿真试验，得到棉花秸秆之间碰撞恢复系数、静摩擦因数、滚动摩擦因数和棉花秸秆-钢之间碰撞恢复系数、静摩擦因数、滚动摩擦因数分别为0.5、0.41、0.06、0.5、0.37、0.08，以及棉花秸秆法向接触刚度、切向接触刚度、临界法向应力与临界切向应力分别为4.15×1010N/m、5.60×1010N/m、40MPa、50MPa。将以上结果进行粉碎试验验证，棉花秸秆粉碎后依据长度和宽度不同，分为粉末型物料、破碎型物料、未破碎型物料，仿真试验质量和实际试验质量之间偏差为6.84%、8.29%、7.37%，证明了参数的可行性，可用于棉花秸秆参数标定。

Discrete Element Simulation Parameters Calibration for Xinjiang Cotton Straw

Due to the lack of accurate simulation model parameters in the process of mechanized harvesting and crushing of cotton straw, there is a great difference between the simulation effect and the actual operation in the design of machinery and tools, which limits the design and research of cotton straw harvesting and crushing device to a certain extent. Xinjiang cotton straw was used as experimental material to carry out simulation analysis. After the intrinsic parameters of cotton straw were determined by physical tests, the EDEM simulation software was used for test simulation and parameter calibration of cotton straw. The accumulation angle and the maximum destructive power of cotton straw were 28.62°and 143.21N respectively by the method of accumulation angle test and bending test. The Hertz-Mindlin no slip model and Hertz-Mindlin with bonding model were used to simulate the stacking angle and bending of cotton straw. The collision recovery coefficient, static friction coefficient and rolling friction coefficient between cotton straw and the collision recovery coefficient, static friction coefficient and rolling friction coefficient between cotton straw and steel were respectively 0.5, 0.41, 0.06, 0.5, 0.37 and 0.08, and the normal contact stiffness, tangential contact stiffness, critical normal stress and critical tangential stress of cotton straw were respectively obtained, which were 4.15×1010N/m, 5.60×1010N/m, 40MPa and 50MPa, respectively. According to the above results, the pulverized cotton straw can be divided into powder type material, crushed type material and unbroken type material according to different lengths and widths. The deviation between the simulation test quality and the actual test quality was 6.84%, 8.29% and 7.37%, which proved the feasibility of the parameters and can be used for the parameter calibration of cotton straw.