基于EDEM的茶园土壤-有机肥混料离散元模型构建与试验

Construction and Experiment of Discrete Element Model for Tea Garden Soil-Organic Fertilizer Mixture Based on EDEM

摘要:

为提高茶园土壤-有机肥混料的离散元模型仿真精度，以茶园土壤与有机肥为研究对象，通过物理试验与仿真模拟相结合的方法进行参数标定。通过斜面法、滚动摩擦试验及碰撞恢复系数测定，获取土壤与有机肥的物理参数及接触参数，并基于圆筒提升法实测混料堆积角。利用Plackett-Burman试验筛选出显著影响参数，结合最陡爬坡试验确定优化区间，通过Box-Behnken响应面法建立二次回归模型，获得最优参数组合：土壤-有机肥恢复系数为0.35、有机肥-有机肥滚动摩擦因数为0.115、有机肥-钢板碰撞恢复系数为0.606。同时通过含水率试验分析明确了模型含水率的适用区间（5%~10%）。验证试验表明，仿真堆积角为24.49°，与实际值相对误差为1.65%。搭建茶园中耕施肥机样机，进行田间和仿真旋耕施肥试验，得到不同旋耕转速（150、200、250、300r/min）条件下，田间试验和仿真试验覆土率的相对误差分别为6.21%、4.52%、7.13%、7.72%，仿真试验与田间试验的土壤-有机肥分布情况相一致，验证了土壤-有机肥混料离散元模型和接触参数的准确性。

Abstract:

Aiming to improve the simulation accuracy of the discrete element model for tea garden soil-organic fertilizer mixture, focusing on the combination of physical experiments and simulation to calibrate the parameters of tea garden soil and organic fertilizer, by using the slope method, rolling friction test, and coefficient of restitution measurement, the physical and contact parameters of soil and organic fertilizer were obtained, and the mixing angle was measured based on the cylindrical lifting method. The Plackett-Burman experiment was used to screen for significant influencing parameters, and the optimization interval was determined by combining the steepest slope test. A quadratic regression model was established by using the Box-Behnken response surface method to obtain the optimal parameter combination: soil-organic fertilizer recovery coefficient of 0.35, organic fertilizer rolling friction factor of 0.115, and organic fertilizer steel recovery coefficient of 0.606. At the same time, the applicable range of moisture content for the model (5%~10%) was clarified through experimental analysis.The verification test showed that the simulated stacking angle was 24.49°, with a relative error of 1.65% compared with the actual value. A prototype of a tea garden tillage and fertilization machine was built, field rotary tillage and fertilization experiments were conducted, and rotary tillage and fertilization experiments were simulated. The relative errors of soil coverage rate in field experiments and simulation experiments at different rotary tillage speeds (150r/min, 200r/min, 250r/min, and 300r/min) were 6.21%, 4.52%, 7.13%, and 7.72%, respectively. The soil-organic fertilizer distribution in simulation experiments was consistent with that in field experiments, verifying the accuracy of the soil-organic fertilizer mixture discrete element model and contact parameters.