基于DEM的玉米秸秆离散元模型参数标定

玉米秸秆外表皮和内瓤的力学特性存在较大差异，为提高玉米秸秆仿真结果的精确度，提出一种基于离散元法(DEM)的玉米秸秆精细化仿真模型建立方法，构建有茎节和无茎节秸秆仿真模型。通过Plackett Burman试验和最陡爬坡试验开展无茎节秸秆模型的单轴压缩仿真试验，确定影响颗粒抗破坏力的因素主要是玉米秸秆外表皮—内瓤滑动摩擦系数、内瓤—内瓤碰撞恢复系数和内瓤—内瓤静摩擦系数，通过正交试验确定最优参数组合为0.28、0.29和0.23。利用有茎节秸秆模型进行剪切试验验证，结果表明仿真试验与物理试验的抗剪切力分别为132.29 N和131.36 N，误差为093 N，说明最优参数组合精确度较高。研究结果可为秸秆还田装置、生物质材料成型和饲料加工装置等关键部件优化设计提供参考依据。

Parameter calibration of corn straw discrete element model based on DEM

The mechanical characteristics of the outer skin and inner pulp of corn straw are quite different. In order to improve the accuracy of the simulation results of corn straw, a method of establishing the refined simulation model of corn straw based on discrete element method (DEM) was proposed, and the simulation models of straw with and without stem nodes were constructed. Through the Plackett Burman test and steepest climbing experiment, the uniaxial compression simulation test of the stalk without stem nodes model was carried out. It was determined that the main factors affecting destructive power of particles were sliding friction coefficient of outer skin inner wall, the collision recovery coefficient of inner wall inner wall, and static friction coefficient of inner wall inner wall. The orthogonal test determined the optimal parameter combination to be 0.28, 0.29, and 0.23. The straw with stem nodes model was used to verify the shear test. The results showed that the shear resistance of simulation and physical tests were 132.29 N and 131.36 N, respectively. The error was 0.93 N, which indicated that the optimal parameter combination had healthy accuracy. The research results can provide reference for the optimization design of critical components such as straw returning devices, biomass materials molding devices, and feed processing devices