Shear Failure Characteristics Of Root Soil Aggregates And Development Of Bionic Desotption Cutter

Conservation tillage is to implement no less tillage and crop stubble covering the surface of farmland.No tillage sowing is to directly sow on the uncultivated ground with stubble and stubble covering.Stubble breaking is the key link affecting the quality of no tillage sowing.In addition,the soil viscosity during spring ploughing is large,the clay phenomenon of stubble breaking tools is obvious,and the working resistance and power consumption increase.Based on the above urgent scientific problems and technical needs,with the support of the Youth Science Foundation Project of the National Natural Science Foundation of China: dynamic shear failure characteristics of corn root soil aggregate and bionic stubble breaking tooth disc(5170051437),this paper focuses on the shear failure characteristics of corn root soil aggregate and desorption bionic tool surface.The main research contents of this paper are as follows:(1)The orthotropic material model of the main part of corn stubble was constructed,and the finite element model was constructed in the software ABAQUS to simulate the tension,compression and shear.Based on the tensile,compression and shear experimental results of the main part of corn stubble,the final tensile,compression and shear simulation is basically consistent with the experimental damage morphology and mechanical properties,which verifies the effectiveness of the orthotropic material model of the main part of corn stubble.(2)CT scanning and root soil separation method are used to realize the in-situ nondestructive reconstruction of corn stubble geometric model,so as to obtain the real corn stubble geometric model under the surface.Based on the in-situ geometric model of corn stubble,the finite element model of root soil aggregate is constructed,and the shear simulation of corn root soil aggregate is carried out.Combined with the shear experiment of corn root soil aggregate,the shear failure characteristics of different parts are explored.It is concluded that the farther away from the middle of the stubble is the better before leaving the stubble cover.(3)Mole cricket,as a soil insect,rarely adheres to the soil on its front chest and back plate when shuttling through the soil for a long time.Through micro CT and other reverse engineering technologies,the overall and local contour configurations are fitted to the surface.It is found that the polynomial reaches order 4 and meets the accuracy requirements.(4)The fitted surfaces of back plate,convex hull and diversion ditch are applied to the bionic desorption surface.Taking the soil vibration response under the action of cutter as the evaluation standard,the soil cutting simulation of bionic desorption surface is carried out.Combined with the shear stripping experimental research of bionic surface,the soil removal ability is obtained: convex hull bionic cutter > back plate bionic cutter > diversion ditch bionic cutter > smooth bionic surface cutter;The bionic surface design parameters with the best desorption effect are convex hull scale34,transverse interval scale 14.37 and longitudinal interval scale 14.