Authors

Abstract

It is difficult to accurately calculate the mutual force and seedling loss law between seedling needles and seedlings when conducting simulation analysis of cutting and transplanting rapeseed blanket seedlings with a transplanting machine due to a lack of reliable discrete element simulation parameters for rapeseed blanket seedlings. The physical and contact parameters of rapeseed blanket seedlings are calibrated in this study using the EDEM discrete element method. The Hertz Mindlin with JKR model in EDEM software was used to simulate the shear force of rapeseed blanket seedlings after conducting experiments to determine the density, shear modulus, Poisson's ratio, friction coefficient, and collision recovery coefficient between seedlings and steel materials. The surface energy parameters, recovery coefficient, static friction coefficient, and rolling friction coefficient between seedlings were used as experimental variables, with the maximum shear force of seedlings serving as the response value. Using Box Behnken's response surface optimization method, multiple regression fitting analysis was performed on the experimental results to obtain the regression model of seedling shear force, which was then optimized to obtain the parameter optimization solution for rapeseed blanket seedlings. Finally, the collision recovery coefficient was calculated to be 0.6. The ideal contact characteristics for seedlings are a static friction coefficient of 0.8, a rolling friction coefficient of 0.3, and a JRK surface energy of 12.3 J/m2.

Abstract in Chinese

在进行油菜毯状苗移栽机切块取苗仿真分析时，由于缺乏可靠的油菜毯状苗的苗片离散元仿真参数，难以准确计算取苗秧针-苗片相互间受力和苗片损失规律。本研究基于EDEM离散元法对油菜毯状苗的苗片物理与接触参数进行标定。通过试验测定苗片密度、剪切模量、泊松比以及苗片-苗片、苗片-钢材料之间的摩擦系数和碰撞恢复系数，采用EDEM 软件中的Hertz-Mindlin with JKR 模型对油菜毯状苗的苗片进行剪切力仿真试验，以苗片间表面能参数、恢复系数、静摩擦系数、滚动摩擦系数为试验因素，以苗片最大剪切力为响应值，基于Box-Behnken的响应面优化方法，对试验结果进行多元回归拟合分析得到苗片剪切力的回归模型，并对回归模型进行寻优，得到油菜毯状苗苗片的参数优化解，最终确定碰撞恢复系数0.6、静摩擦系数0.8、滚动摩擦系数0.3、JRK表面能 12.3 J/m2是苗片的最优接触参数组合。