基于离散元的微型马铃薯仿真参数标定

为系统全面地研究微型马铃薯种子离散元仿真物性参数,根据其物料特征创建微型薯模型,以此为基础建立微型薯离散元参数获取模型。利用试验测定及仿真模拟相结合的方法对微型薯颗粒离散元参数进行标定和校准,即以先后建立碰撞恢复系数测定模型、微型薯-钢板摩擦因数测定模型、微型薯颗粒间摩擦因数测定模型的方法,在EDEM中建立仿真试验模型并以所标定的相应离散元仿真参数为自变量,以仿真模型所测定的因素为评价指标,通过在仿真模型中改变自变量获取相应的评价指标值,建立曲线拟合方程,将真实试验模型中对各因素所测定的值作为仿真目标值代入拟合方程中得到微型薯离散元仿真参数并进行了仿真试验验证。求得微型薯种子离散元仿真参数:微型薯-钢板碰撞恢复系数为0.523,微型薯颗粒间碰撞恢复系数为0.478,微型薯-钢板静摩擦因数为0.644,微型薯-钢板滚动摩擦因数为0.022 1,微型薯颗粒间静摩擦因数为0.325,微型薯颗粒间滚动摩擦因数为0.030 0。对标定后的微型薯离散元物性参数进行仿真验证试验,结果表明标定后的微型薯仿真颗粒堆积角以及种子分布情况与真实试验条件相吻合,为微型薯相关播种机具设计和优化提供了理论依据。

Calibration of Simulation Parameters for Potato Minituber Based on EDEM

In order to study the discrete element simulation physical parameters of potato minituber, the combination methods of experiment and simulation were used to calibrate contacting parameters of particle discrete simulation. The simulation experimental model was built in EDEM by using coefficient measurement model of restitution, particle-steel friction coefficient measurement model and particle-particle coefficient friction measurement model. The corresponding contacting parameters of particle discrete element was used as independent variable, the data which was measured by simulation model was used as evaluation index, and then curve fitting equation was built by changing the independent variables to obtain the corresponding evaluation index value in the simulation model. Finally, the factors measured in the real test model were substituted into curve fitting equation as the simulation target values to obtain the discrete element simulation contact parameters of potato minituber. The simulation experiment was verified through repeated simulation experiments. The particle discrete element simulation target parameters were obtained as the particle-steel coefficient of restitution was 0.523, the particle-particle coefficient of restitution was 0.478, the particle-steel coefficient of static friction was 0.644, the particle-steel coefficient of rolling friction was 0.0221, the particle-particle coefficient of static friction was 0.325 and the particle-particle coefficient of rolling friction was 0.0300. The calibrated physical parameters of the potato minituber were simulated by EDEM. The result showed that the calibrated particle stacking angles and seed distribution were consistent with the real experimental conditions. Simultaneously, the result can provide theoretical basis for the design and optimization of potato minituber related sowing equipment.