Authors

Abstract

Soils in China's Yangtze River Basin are heavy and cohesive. During simulation studies of rotary tillage preparation, obtaining accurate soil fragmentation patterns has been challenging due to the lack of precise soil discrete element parameters. This study calibrated the physical and contact parameters of heavy clay soils using the EDEM discrete element method. Soil density, shear modulus, Poisson's ratio, collision recovery coefficient, static friction coefficient, and rolling friction coefficient between soil-soil and soil-tiller components were experimentally determined. Soil penetration tests were conducted using the Hertz-Mindlin with JKR contact model in EDEM software. A Plackett-Burman design identified four parameters significantly influencing soil penetration stiffness: soil-soil collision recovery coefficient, soil-soil static friction coefficient, JKR surface energy, and soil-soil rolling friction coefficient. Building upon this, a second-order regression model linking soil firmness to key parameters was established via Box-Behnken experiments. An optimization algorithm was then employed to determine optimal parameter values, yielding the following combination: soil-soil static friction coefficient 0.441, soil-soil collision recovery coefficient 0.537, and JKR surface energy 9.551 J/m². Validation results demonstrated that under optimal parameters, the simulation error of soil stiffness compared to experimental data was only 3.0%, confirming the accuracy of the calibrated parameters.

Abstract in Chinese

中国长江流域土壤黏重，在旋耕整地仿真研究时，由于缺乏准确的土壤离散元参数，难以得到准确的土壤破碎规律。本研究基于EDEM离散元法对黏重土壤的物理与接触参数进行标定。试验测定土壤密度、剪切模量、泊 松比以及土壤-土壤、土壤-触土部件间的碰撞恢复系数、静摩擦因数和滚动摩擦系数，采用EDEM软件中Hertz-Mindlin with JKR接触模型对土壤进行穿刺试验。采用Plackett-Burman试验筛选出对土壤穿刺试验坚实度影响显著的四个参数：土壤-土壤碰撞恢复系数、土壤-土壤静摩擦因数、JKR表面能及土壤-土壤滚动摩擦系数。在此基础上，通过Box-Behnken试验建立了土壤坚实度与关键参数间的二阶回归模型，并采用优化算法进行参数寻优，最终获得最优参数组合：土壤-土壤静摩擦因数0.441，土壤-土壤碰撞恢复系数0.537，JKR表面能9.551 J/m²。验证结果表明，在最优参数条件下，土壤坚实度的仿真结果与试验结果误差仅为3.0%，证明了参数标定的准确性。