基于离散元仿真的颗粒虾饲料参数标定与试验

Parameter Calibration and Experiment Verification of Shrimp Feed Pellet Based on Discrete Element Method

摘要:

为系统标定颗粒虾饲料本征参数、颗粒间及颗粒与装备间接触参数，提高颗粒虾饲料下料、输送及机械抛撒等环节离散元仿真优化的性能和精度，以通威柱形沉性颗粒虾饲料为研究对象，通过物理试验和仿真试验相结合的方法进行颗粒虾饲料离散元仿真参数标定。采用高精度数显卡尺、电子秤及压力试验机等仪器，应用物理试验方法测定颗粒虾饲料的密度、泊松比、弹性模量、剪切模量分别为1177.68kg/m3、0.26、114.77MPa、45.58MPa，通过斜面试验和回弹试验测得颗粒虾饲料与304号不锈钢之间静摩擦因数、滚动摩擦因数、恢复系数分别为0.607、0.097、0.35，进行堆积试验得到颗粒虾饲料堆积角平均值和饲料在钢板上面积占比分别为26.93°和13.32%。基于Plackett-Burman试验筛选出对仿真堆积角和面积占比显著影响因素为颗粒虾饲料-颗粒虾饲料静摩擦因数、颗粒虾饲料-颗粒虾饲料滚动摩擦因数和颗粒虾饲料-304号不锈钢静摩擦因数，在此基础上，应用最陡爬坡试验收敛寻优范围，并通过Box-Behnken Design试验拟合显著影响因素与响应值之间的回归方程进行参数优化，得到最优参数组合：颗粒虾饲料-颗粒虾饲料静摩擦因数0.207，颗粒虾饲料-颗粒虾饲料滚动摩擦因数0.150及颗粒虾饲料-304号不锈钢静摩擦因数0.607。用堆积试验和螺旋下料试验进行参数可靠性验证，结果表明：经过双样本t检验，堆积试验仿真结果与物理堆积结果无显著差异，不同转速下仿真试验和物理试验的下料量折线的相关系数为0.997，趋势一致且各转速下下料量相差小于3%，表明了标定的颗粒虾饲料离散元参数的可靠性与正确性。所标定的离散元参数能为颗粒虾饲料运动机理研究和相关装备设计优化离散元仿真提供数据基础和科学依据。

Abstract:

In order to improve the performance and accuracy of discrete element method simulation optimization in the processes of blanking, conveying, and mechanical spreading of the shrimp feed pellet, the intrinsic parameters of the shrimp feed pellet, the contact parameters between feed, the contact parameters between feed and equipment were systematically calibrated. Taking Tongweis columnar sinking shrimp feed pellet as research object, the DEM simulation parameters of the shrimp feed pellet were calibrated by combining physical and simulation experiments. Firstly, by using the physical test method, the density, Poisson’s ratio, elastic modulus and shear modulus of the shrimp pelleted feed were measured to be 1177.68kg/m3, 0.26, 114.77MPa and 45.58MPa, respectively through instruments such as high precision digital calipers, electronic balances and pressure testing machines. Through inclined plane method and rebound method, the static friction coefficient, rolling friction coefficient, and restitution coefficient between the shrimp feed pellet and 304 stainless steel were determined to be 0.607, 0.097 and 0.35, respectively. The average stacking angle of the shrimp feed pellet was found to be 26.93°, and the feed’s area coverage on a steel plate was 13.32% through stacking tests. Secondly, based on the Plackett-Burman experiment, the factors significantly affecting the physical stacking angle and area proportion were screened out to be the static friction coefficient between feed, the rolling friction coefficient between feed, and the static friction coefficient between feed and 304 stainless steel. Based on this foundation, the steepest ascent experiment was applied to converge the optimization range, and the parameter optimization was carried out by fitting the regression equation between the significant influencing factors and the response values through the Box-Behnken Design experiment. The optimal parameters combination were obtained as follows: the static friction coefficient between feed was 0.207, the rolling friction coefficient between feed was 0.150, and the static friction coefficient between feed and 304 stainless steel was 0.607. Finally, the reliability of the parameters was verified through stacking tests and spiral blanking tests. The findings revealed that the simulated stacking test results were statistically indistinguishable from the physical counterparts, as confirmed by a double-sample t-test. Furthermore, the correlation coefficient between the simulated and physical tests for the discharge amount line under varying speeds was an impressive 0997, signifying a highly consistent trend with a discrepancy in discharge amount of less than 3% across all speeds. These results underscored the reliability of the calibrated DEM parameters for shrimp pellet feed, thereby establishing a solid data foundation and scientific rationale for investigating the motion mechanisms of shrimp feed pellets and optimizing equipment designs within DEM simulations.