黑土区玉米秸秆-土壤混料离散元模型参数标定

由于黑土区保护性耕作中关键农机部件设计优化过程中缺乏准确的离散元仿真模型参数，在一定程度上制约了机具的优化改进。以黑土区玉米秸秆-土壤混料为研究对象，构建玉米秸秆-土壤混料离散元仿真模型，采用物理试验与EDEM仿真试验相结合的方法，选用Hertz-Mindlin with JKR接触模型进行离散元仿真接触参数标定。首先，采用圆筒提升的方法确定玉米秸秆-土壤混料的实际堆积角，利用Design-Expert软件中Plackett-Burman试验筛选出对堆积角有显著影响的参数为：土壤-土壤滚动摩擦因数、土壤-钢静摩擦因数、秸秆-土壤滚动摩擦因数、土壤JKR表面能；进一步通过最陡爬坡试验确定4个参数的最优取值范围，根据Box-Behnken试验原理以堆积角为响应值，建立堆积角与显著参数的二次回归模型；以实际堆积角为目标，利用软件寻优功能对显著参数进行优化并得到最优参数组合：秸秆-土壤滚动摩擦因数0.16、土壤-土壤滚动摩擦因数0.24、土壤-钢静摩擦因数0.75、土壤JKR表面能0.67J/m2。通过仿真试验对最优参数组合进行对比验证，仿真堆积角与物理试验堆积角相对误差为1.64%。研究结果表明标定的参数真实可靠，可为黑土区玉米秸秆-土壤混料的离散元仿真提供理论参考。

Parameter Calibration of Discrete Element Model for Corn Straw-Soil Mixture in Black Soil Areas

Due to the lack of accurate discrete element simulation model parameters in the design optimization process of key agricultural machinery components under conservation tillage in black soil area, the optimization improvement of the machinery and tools is restricted to a certain extent. In order to obtain the accurate discrete element simulation contact parameters of the corn straw-soil mixture in the black soil area, the discrete element simulation model of the corn straw-soil mixture was constructed. The physical test and the EDEM simulation test were combined and the Hertz-Mindlin with JKR contact model was used for discrete simulation contact parameter calibration. Using the Plackett-Burman test in the Design Expert software, the parameters that had a significant impact on the repose angle were selected as follows: soil-soil rolling friction coefficient, soil-steel static friction coefficient, straw-soil rolling friction coefficient, soil JKR surface energy; and the optimal value range of the four parameters were further determined through the steepest climbing test. According to the Box-Behnken test principle, the repose angle was used as the response value to establish a quadratic regression model between the repose angle and the significant parameters; the actual repose angle was used as the target, and the software was used to optimize. The function optimized the significant parameters and the optimal parameter combination was obtained as follows: straw-soil rolling friction coefficient was 0.16, soil-soil rolling friction coefficient was 0.24, soil-steel static friction coefficient was 0.75, and soil JKR surface energy was 0.67J/m2. The optimal parameter combination was compared and verified through simulation experiments, and the relative error between the simulated repose angle and the physical test repose angle was 1.64%. The research results showed that the calibrated parameters were true and reliable, which can provide a theoretical reference for the discrete element simulation of the corn straw-soil mixture in the black soil area.