Experimental Study on Shear Mechanical Characteristics of Jujube Branches in Winter Pruning Period

The objective of this study was to design and optimize the pruning and crushing machinery of jujube branches, and to provide the corresponding data reference, so as to improve the cutting and crushing efficiency of jujube branches. Take fresh jujube branches (31.7±5 % w.b) as the research object. The morphology and microstructure of jujube branches were detected by scanning electron microscope. Four kinds of cutting blades were selected and manufactured, and the cutting characteristics of four kinds of blades against branches were evaluated. The shear fracture process of jujube branches was analyzed according to the microstructure of branches. Covariance analysis was used to separate the influence of water content on shear strength, and the significance level of the influencing factors is evaluated. The analysis of the test results showed that: the significant effects on shearing strength of the branches are shearing angle, cutter shape and shear speed from large to small. The force-displacement curves of cutting tool branches with different shapes of edge lines are different, and the peak of the shear force generally appears in the II&IV stages (xylem) shearing process. Under the same shear mode and the same shear velocity, the shear strength of the cambered cutter is the smallest.