Authors

Abstract

During the mechanized harvesting of Laminaria japonica, it is prone to breakage and damage, resulting in an increased loss rate. To accelerate the optimization of harvesting equipment for Laminaria japonica, this study established a simulation model based on the discrete element method. The Hertz-Mindlin with Bonding contact model was used, and parameters of Laminaria japonica were calibrated through shear tests. Using the maximum shear force (Fmax) as the test indicator, the optimal parameters were obtained through Plackett-Burman test, the steepest climb test, Box-Behnken test, and the GP-PSO-XGBoost regression prediction model. The results indicated that when the coefficient of restitution of Laminaria japonica-steel was 0.45, the normal stiffness per unit area was 303 MN/m3, the shear stiffness per unit area was 378 MN/m3, and the bonding radius was 0.70 mm, the relative error of Fmax was 0.75%. The average error of the Fmax for samples at different thicknesses was 3.09%, and the relative error of the maximum puncture force in puncture test was 5.59%. Finally, a discrete element model of the whole Laminaria japonica was established. This study offers theoretical support for the development and optimization of harvesting equipment for Laminaria japonica.

Abstract in Chinese

海带在机械化采收过程中易出现破损和损伤，造成损失率增加。为了加速海带机械收获设备的研发，本研究基于离散元法建立了海带仿真模型。研究采用Hertz-Mindlin with Bonding接触模型，通过剪切试验对海带进行参数标定。以最大剪切力（Fmax）为试验指标，通过Plackett-Burman检验、最陡爬坡检验、Box-Behnken检验和GP-PSO-XGBoost回归预测模型得到最优参数。结果表明：当海带钢的恢复系数为0.45，单位面积法向刚度为303 MN/m3，单位面积剪切刚度为378 MN/m3，粘接半径为0.70 mm时，Fmax的相对误差为0.75%。不同厚度样品的Fmax平均误差为3.09%，穿刺试验中最大穿刺力的相对误差为5.59%。最后，建立海带整体的离散元模型。本研究为海带收获设备的研发与优化提供理论支持。