基于离散元法的胡萝卜挖掘铲优化设计

Optimal Design of Carrot Digging Shovel Based on Discrete Element Method

针对胡萝卜联合收获机工作过程中松土挖掘阻力大、胡萝卜漏拔率高等问题,对收获状态下三角翼形挖掘铲进行受力分析和计算,确定了铲面宽度和铲刃角的取值范围。根据胡萝卜种植模式,建立了挖掘铲-胡萝卜-土壤离散元仿真模型,以挖掘铲面长度、宽度及铲刃倾角为试验因素,以挖掘阻力、土壤破碎率为试验指标开展了胡萝卜挖掘仿真试验,仿真时间历程显示了土壤与胡萝卜随挖掘铲运动的变化过程。利用仿真试验数据拟合建立不同试验因素影响下挖掘铲阻力与土壤破碎率的二次多元回归方程,通过Design-Expert 10.0.7对数学模型进行分析求解,得出了最优参数组合为:铲面长度260mm,铲面宽度370mm,铲刃倾角57°。通过与凿型铲进行对比试验,结果表明:工作阻力降低了9.4%,土壤破碎率提高了2.8%,优化设计的三角翼形挖掘铲在工作阻力和土壤破碎率方面具有良好的松土性能,满足胡萝卜收获要求。研究可为胡萝卜挖掘装置试验研究和设计提供理论参考。

Aiming at the problems of large operating resistance and high leakage rate of carrot combine harvester,the stress analysis and calculation design of triangular digging shovel under the condition of carrot harvest were carried out,and the value range of shovel surface width and shovel edge angle were determined.According to the carrot planting mode,the discrete element simulation model of shovel-carrot-soil was established.The carrot digging simulation test was carried out with the shovel surface length,shovel surface width and shovel edge inclination as the test factors and the operating resistance and soil fragmentation rate as the test indexes.The simulation time history shows the change process of soil and carrot with the movement of the digging shovel.The quadratic multiple regression equation of digging shovel resistance and soil crushing rate under the influence of different test factors is established by fitting the simulation test data.The mathematical model is analyzed and solved by design expert 10.0.7.The optimal parameter combination is obtained as shovel surface length 260mm,shovel surface width 370mm and shovel edge inclination 57°.Through the field test,the working resistance was reduced by 9.4%and the soil crushing rate was increased by 2.8%in the comparison test with the chisel shovel,indicating that the two-wing open triangular shovel with optimized design has good loosening performance in terms of working resistance and soil crushing rate,which meets the carrot harvesting requirements and provides the theoretical basis for the experimental research and design of carrot digging device.