金乡紫皮蒜种离散元参数标定与试验验证

Calibration and Verification of Discrete Element Parameters of Jinxiang Purple Garlic Seeds

针对蒜种在播种仿真试验时缺乏参数的问题,以金乡紫皮蒜种为研究目标,测量蒜种的物性参数并对蒜种的离散元仿真参数进行标定。测定了蒜种的密度、含水率、泊松比、剪切模量、静摩擦系数、滚动摩擦系数以及碰撞恢复系数,以多个物性参数为试验因素,以蒜种堆积角为试验指标进行Plackett-Burman试验,筛选出对堆积角影响显著的因素为蒜种间静摩擦系数及滚动摩擦系数。以物理试验结果为最优值,通过CCD响应曲面试验对显著因素进行优化,优化后蒜种间最佳静摩擦系数和滚动摩擦系数分别为0.428和0.287。以转速为试验因素,以多粒率为试验指标,以自制链勺式大蒜排种器装置进行试验验证,结果表明,仿真与测量结果平均相对误差较小,变化折线图趋势相一致,优化标定的蒜种仿真参数具备一定的可靠性,可以为大蒜播种机的仿真试验提供数据支撑。

Aiming at the problem of lacking parameters in garlic seeding simulation test,this paper took Jinxiang purple garlic species as the research material,measured the physical property parameters of garlic and calibrated the discrete element simulation parameters.The density,water content,Poisson’s ratio,shear modulus,static friction coefficient,rolling friction coefficient and collision recovery coefficient of garlic were determined by experimental method.Through Plackett-Burman test with several physical parameters of garlic as test factors and garlic accumulation angle as test index,the factors significantly affecting accumulation angle were selected as static friction coefficient and rolling friction coefficient between garlic plants.Then,the significant factors were optimized by CCD response surface test,and the physical test results were taken as the optimum values.The optimum static friction coefficient and rolling friction coefficient between garlic crops were 0.428 and 0.287,respectively.Taking rotational speed as the test factor and multi-grain rate as the test index,the simulation and bench comparative test verification of self-made chain scoop garlic planter device were carried out.The results showed that the average relative error between simulation and measured results was small,and the change curve was consistent,and the optimized and calibrated garlic simulation parameters had certain reliability,which could provide data support for garlic planter simulation test.