Authors

Abstract

To accurately simulate the interactions between the plug seedlings and the planter during the planting process and explore the damage mechanism of the plug seedling substrate block, the bonding parameters of plug seedlings substrate block were calibrated by the discrete element method. The physical puncture test showed that the average of maximum force of the cone indenter on substrate block measured by texture analyzer was 4.633 N. A Hertz-Mindlin with the bonding model was established for the substrate block in EDEM software. A virtual calibration experiment was designed with the puncture force of substrate block as the evaluation index. The two-level factorial test and the steepest climbing test were used to screen out the significant parameters and the optimal interval. Then, the Box-Behnken test and the optimization solution were used to obtain the optimal bonding parameter combination of the substrate block particles. Finally, the optimal parameter combination was simulated and verified. The relative error of the maximum puncture force between the simulated value and the measured value was 1.88 %, which indicated that the bonding parameters of the substrate block obtained by calibration were accurate and reliable.

Abstract in Chinese

为准确模拟栽植过程中穴盘苗与栽植器间的相互作用，探究穴盘苗基质块的破损机理，采用离散元法校准了穴盘苗基质块的粘结参数。通过物理穿刺试验测得锥形压头对基质块的最大穿刺力平均值为4.633 N。应用Hertz-Mindlin with bonding模型对基质块进行建模，并以最大穿刺力为评价指标，采用二水平析因试验和最陡爬坡试验筛选出显著性参数和最优区间，通过Box-Behnken试验和优化求解，得到基质块颗粒的最佳粘结参数组合，针对最优参数组合进行仿真验证，得出仿真值和实测值最大穿刺力相对误差为1.88%，表明标定所得基质块粘结参数准确可靠。