葱白力学特性参数的试验研究

Experimental Study on Mechanical Properties of Scallions White

收获期大葱葱白的结构尺寸及含水率等影响大葱收获方案、夹持位置和铺放流程的设计,掌握葱白的力学特性,可为大葱的夹送收获方式及收获过程仿真研究提供支持。为此,借助Design-Expert12软件的四因素三水平方案,确定含水率、位置、直径、加载速度对葱白抗压强度及剪切强度的影响规律,且位置对抗压强度及剪切强度的影响显著。通过葱白力学参数测定数据的统计分析,确定葱白各部分的力学特性差异不大,主要受葱白组织结构的影响,且中部的抗压强度及剪切强度较弱,上部和下部相近。试验结果表明:葱白上部抗压强度平均值为0.33MPa,弹性模量平均值为2.44MPa;葱白中部抗压强度平均值为0.37MPa,弹性模量平均值为2.76MPa;葱白下部抗压强度平均值为0.39MPa,弹性模量平均值为2.56MPa;葱白上部剪切强度平均值为0.207MPa,葱白中部剪切强度平均值为0.19MPa,葱白下部剪切强度平均值为0.21MPa。由此可见,大葱葱白力学特性差异不大可视为匀质体,被夹持位置应尽量夹在上部与下部,从而减少大葱的收获损伤。

The structure,size and moisture content of the scallion white at its harvest time affect the design of scallion harvesting scheme,clamping position and laying process.Mastering the mechanical properties of scallion white can provide support for the clamping harvesting method and the simulation research of the harvesting process of scallion.Using the Desk-Expert12 software’s four-factor,three-level solution,the influence of moisture content,location,diameter,and loading speed on the compressive strength and shear strength of green onion was determined,and the influence of location on the compressive strength and shear strength was significant.Through the statistical analysis of the mechanical parameters of the scallion white,it was determined that the mechanical properties of the different parts of the scallion white were not different,which was mainly affected by the structure of itself.Besides,the compressive strength and shear strength of the middle part were weak,and the upper and lower parts were similar.The experimental results showed that the average compressive strength and elastic modulus of the upper part of scallion white were 0.33MPa and 2.44MPa respectively.The average compressive strength and elastic modulus in the middle of the scallion white are 0.37MPa and 2.76MPa respectively.The average compressive strength of the lower part of scallion white is 0.39MPa,and the average elastic modulus is 2.56MPa.The average shear strength of the upper part of scallion white was 0.207MPa.The average shear strength in the middle of scallion white was 0.19MPa.The average lower shear strength of scallion white was 0.21MPa.Thus it can be seen that the mechanical properties of scallion white are not very different and can be regarded as homogenous body.The clamping position should be as far as possible between the upper and lower parts to reduce the harvest damage of scallion.