Abstract: The physical parameters of chili seeds are important inputs in the discrete element simulation. In order to improve the reliability and accuracy of the numerical simulation, the physical property parameters of capsicum seeds were measured experimentally, including triaxial size, density, Poissons ratio, friction coefficient, recovery coefficient, et al. Combined with the “Hertz Mindlin with JKR” viscosity model in EDEM, surface energy parameters were introduced to conduct the angle of repose test. The three most significant influencing parameters (chili seedseed rolling friction coefficient, chili seed surface energy, and chili seedsteel plate rolling friction coefficient) were selected among the influencing factors by PlackettBurman test, and the regression model of the three significant influencing parameters and the angle of repose was established to study the influence of the significant factors on the angle of repose under the interaction effect. The interval of significant parameters was divided into 5 levels by gradient average for climbing test to get the optimal range of values, and finally the response surface method (BoxBehnken) was applied to analyze the variance of the quadratic polynomial of the regression model in terms of the angle of repose, the relative error and the three important parameters, and the model was optimized with the minimum value of relative error to get the optimal combination: rolling friction coefficient between chili seeds was 0.75, JKR surface energy was 0.31J/m2, and rolling friction coefficient between chili seeds and steel plate was 0.60. The optimal combination of parameters obtained from the calibration test was used to conduct the simulated stacking test, and the average angle of repose was 26.71°, and the relative error was 4.61%.

Key words: chili seeds, parameter calibration, JKR contact model, response surface method, EDEM, agricultural products

摘要： 辣椒籽的物性参数是离散元仿真中重要的输入，为提高其数值模拟的可靠性与准确度，对辣椒籽的物性参数进行试验测量，主要包括三轴尺寸、密度、泊松比、摩擦系数、恢复系数等。结合EDEM中“HertzMindlin with JKR”粘力模型，引入表面能参数，进行休止角试验。通过PlackettBurman试验在各影响因子中筛选出最具显著性的3个影响参数（辣椒籽—籽滚动摩擦系数、辣椒籽表面能、辣椒籽—钢板滚动摩擦系数），建立3个显著影响参数与休止角的回归模型，研究显著因子在交互作用下对休止角的影响。将显著参数的区间按梯度平均分为5个水平进行爬坡试验得到最佳取值范围，运用响应面法(BoxBehnken)分析回归模型的二次多项式在休止角、相对误差和三个重要参数之间的方差，以相对误差最小值对模型进行优化，得到最优组合：辣椒籽间的滚动摩擦系数为0.75、JKR表面能为0.31J/m2、辣椒籽与钢板间滚动摩擦系数为0.60。用通过标定试验得到的最优参数组合进行模拟堆积试验，平均休止角为26.71°，相对误差为4.61%。

关键词: 辣椒籽, 参数标定, JKR接触模型, 响应面法, EDEM, 农产品加工