Design And Experimental Study On Ditching Device Of Chain Ditcher For Camellia Oleifera Forest Land

Ditching is an important part of Camellia forest tending.At present,the ditching operation of Camellia oleifera forest in southern China mainly relies on manual completion,with high labor intensity and low operation efficiency.Aiming at the problems of complex working environment,harsh ditching conditions and difficulty in deep ditching(>300mm)in southern Camellia oleifera forest land,the research group designed a chain ditcher for Camellia oleifera forest land.In this paper,the three-dimensional model of the ditching device of the chain opener for Camellia oleifera forest land was established by CATIA three-dimensional software.With the help of ANSYS,LS-DYNA and other simulation software,the following research was carried out on the ditching device:(1)According to the agronomic requirements of deep ditching operation in Camellia oleifera forest land,the overall design scheme and main operation parameters of ditching machine were determined.The motion parameters and dynamic parameters of the ditching device are analyzed,and the power required for the ditching operation is calculated.The key components of the ditching device are designed,and the three-dimensional model of the ditching device is established.(2)The blade-soil cutting simulation model is established,and the process of blade cutting soil is studied and analyzed.The variation of equivalent stress,cutting resistance and cutting energy consumption in the process of cutting soil is obtained.On this basis,a three-factor and three-level simulation test was established with the average cutting resistance as the index to explore the influence of the three factors of blade thickness,cutting depth and cutting speed on the average cutting resistance.The optimal parameter combination for the minimum average cutting resistance is the blade thickness of 6 mm,the cutting depth of 20 mm,and the cutting speed of 7.7 m/s.(3)The static and modal analysis of the finite element model of the ditching device was carried out.The stress,strain and displacement distribution cloud diagram of the ditching device obtained by static analysis shows that the maximum stress value at the maximum stress point of the ditching device is less than the yield limit of the manufacturing material,and the deformation here is small,indicating that the strength and stiffness of the ditching device meet the requirements.The natural frequency of the trenching device and the modal shape diagram of each order obtained by modal analysis show that the working frequency of the trenching device can avoid the natural frequency and there will be no resonance phenomenon,which verifies the safety and rationality of the design of the ditching device.(4)The ditching test of Camellia oleifera forest land shows that the ditching device works stably and reliably,and the quality of ditching operation is good.The ditch excavated from the test is flat,the ditch wall is smooth,and the soil at the bottom of the ditch is less.The average ditching depth of the ditching test was 416.9 mm,and the average ditching width was 206.8 mm,which met the agronomic requirements of deep ditching in Camellia oleifera forest land.According to the test results,the average cutting resistance test value is basically consistent with the simulation value,and the average error of the optimal parameter combination is 5.1%,which achieves a good drag reduction effect.