Experimental Study Of Mechanical Properties Of Jujube Pruning Branches In Xinjiang

Jujube pruning branches resource,with high lignocellulose content is a by-products of jujube industry and a good renewable biological resources.With the rapid development of the XinJiang jujube industry,jujube pruning branches yield increase rapidly,it has averaged over1.9 million tons since 2012.At present,the utilization rate of jujube trees in Xinjiang is very low,partly because of the use of incineration of pests and other jujube farmers,and the second is because the jujube trees are very time-consuming and laborious.Environmental pollution and waste of resources,the urgent need to introduce agricultural machinery to solve the current Xinjiang jujube remnants of the recycling problem.In this study,the microstructures of jujube trees were studied by combining material mechanics with microstructures of residual trees,and the internal stress changes of jujube trees were studied under various load conditions.The results showed that the mechanical properties of jujube stubble under compressive,shear and bending load conditions provided a valuable reference for the processing of jujube stubble,which was provided the theoretical basis for the design and manufacture of residual processing machinery.In this study,the morphological characteristics,the composition and microstructure of lignocellulose of jujube trees were studied.The compressive test,shear test,bending test and impact test were carried out.And the relevant data needed for finite element modeling are obtained.The finite element modeling is used to analyze the residual force.The main conclusions are as follows:(1)Through the morphological observation,moisture content and lignocellulose determination,it was found that the annual chrysanthemum was similar to the lignocellulose content of the general wood.The diameter of the stubble branches is approximately normal distribution,the overall range is between 10mm and 18mm,the length of the jujube stubs is relatively balanced,the whole is between 600 and 1000mm,the weight of the jujube stubble is approximately normal distribution,the overall range Between 100-180g.There was a significant correlation between the diameter of the sticks and the weight of the sticks.The content of cellulose was about 35.0%,the lignin content was about 24.4%and the hemicellulose content was about 16.8%.This is similar to the wood content of lumber lignin,which is higher than that of cotton and other agricultural stalks.(2)through the microstructure observation found that the catheter and more scattered,more wood rays,parenchyma parenchyma cells loose,wood fiber cells arranged neatly,parenchyma cell content rarely.It can be seen from the structure that the stem-stem structure contains the fibroblast population,and the transverse structure of the wood ray is more,the stem-like tensile force will be significantly higher than the lateral;the xylem structure is similar to the loose structure of the wood,And the impact of shear strength;and the number of wood fibers accounted for less impact on the impact of residual bending strength.By contrast,jujube stubble xylem similar structure and wood in the early structure,which is consistent with the morphological observation and lignocellulose determination results.(3)jujube stubble stripe compression to the maximum load,cross-section compression direction of the catheter deformation is large,wood fiber deformation uniform,no cracks;in the residual bending bending,the wood bending damage occurred first in the pull-end.The initial cracks are often generated in the catheter wall,due to stress concentration,in the catheter wall will continue to appear a lot of micro-cracks,through continuous loading,micro-cracks throughout the destruction of the catheter,the fiber pull-out at the pull-out.(4)The finite element analysis shows that the maximum deformation of the residual branch is 12.041mm,the position of the maximum deformation is the middle of the residual branch,and the deformation of the residual branch is symmetrical with respect to the middle of the residual branch.The actual shear deformation is similar.The maximum equivalent stress is 740.38MPa and the minimum equivalent stress is 0.28837MPa.(5)The results of density and surface hardness showed that the residual density was837kg/m~3,which was consistent with the weight of jujube remnants.The surface hardness of40-45 MPa was the surface hardness of red dates.Concentrated distribution of the area,with a rough control of wood hardness can be regarded as moderate hardness of the wood.The impact energy of the cuttings is approximately normal distribution,and the impact capacity of the cut specimen is mainly distributed in the range of 0-20J.The structure of the residual branch affects the impact result,and the area containing the section will increase significantly.This should be taken into account when the mechanical design is carried out.The results of density determination and surface hardness of jujube stubble affected the impact experiment to a certain extent.(6)The compressive and shear tests show that the rupture force,the elastic modulus and the rupture relative deformation of the residual lines are equal.When the water content is 6%,the anti-compression mechanical properties of the residual branches have anisotropy,and the anti-compression performance in the direction of the residual grain is better than that in the smooth direction.(7)The shear test shows that the middle part of the residual load is better than the experimental loading position,and the peak shear force is 4125.261N,which belongs to the most easy cutting position.This result is basically consistent with the simulation results.