Optimum Design And Experimental Of Rice Straw Deep-buried Roller Assembly Based On Discrete Element Method

The rational utilization of straw resources has become an urgent problem to be solved,due to a series of environmental problems such as haze caused by straw burning in recent years.High collection cost because northeast China is a vast area which restricts the diversified utilization of straw.Straw mechanized returning to field and fertilizing soil has become the first choice for straw utilization.Comprehensive analysis of various mechanized returning methods shows that rice straw deep-buried returning to field is one of the effective ways of returning straw to field,which is suitable for cultivation depth and does not affect subsequent transplanting operations,and can avoid problems such as straw floating.Aiming at the problems of accumulated soil in front of the machine and large power consumption in the present rice straw deep-buried returning machine,this paper,based on consulting a large number of relevant literature and analyzing the current research at home and abroad,in order to achieve the goal of high efficiency,low cost and increase income under the premise of meeting the agricultural requirements of rice straw deep-buried returning machine,optimizes the blade roller assembly which the key component of the rice straw deep-buried returning device.Through theoretical analysis,structural design,computer numerical simulation analysis,bench test and field test,the main research contents as follows:(1)Optimum design of blade roller assembly for deep-buried rice straw returningThe optimum design of the blade roller assembly for deep-buried rice straw returning was carried out.The overall structure and working principle of the device were expounded.The knife edge curve was designed as a combination of multi-section curves.By analyzing the mechanism of force between the blade and soil,the mathematical theoretical model of power consumption of the blade was constructed.The main geometric factors affecting the powe r consumption of the blade were blade width and the bending angle and the bending line angle,theoretical basis for blade optimization design was provied.In order to meet the technical requirements of deep-buried rice straw returning to the field,the diameter of the cutter roll was 240 mm and the arrangement was spiral.(2)Numerical simulation analysis and test of blade roller assemblyIn order to explore the influence of tool geometry on power consumption and soil-throwing performance,the mechanism of coupling of rice straw-soil-machine tools is analyzed,and the variation law between multi-factor and multi-objective is explored,and the optimal parameters of low-lying soil and power consumption are obtained.The virtual simulation experiment was carried out,and the knife width,bending line angle and bending angle were selected as the test factors.The number of soil particles before the throwing,the amount of soil particles to be thrown and the power consumption were optimized for the evaluation index,and the tool was designed by Design-Expert8.0.6 software.The performance of the soil and the power consumption are optimized to obtain the optimal geometric parameter combination of the tool.The results show that when the knife width is 79 mm,the bending line angle is 56° and the bending angle is 81°,the tool performance is optimal.The number of particles thrown before the soil is 2862,the number of particles after the soil is 2037,and the torque of the knife roll is 1.803N·m.The back-roller torque is reduced by 18.33%,which verifies the rationality of the design.(3)Vibration modal test of bladeTaking rice straw deep-buried blade roller as the research object,the finite element modal simulation analysis was carried out.The vibration frequencie s and modes of each stage of blade roller were obtained,and the vibration modal test bench was built.The actual vibration frequencies and modes of each stage of cutter roller were obtained by hammering test.The error range was 3.02%-11.58%,which verified the accuracy of modal test of each stage.The external excitation frequency lower than its own frequency,there will be no resonance phenomenon,and the blade roller design is reasonable.(4)Bench test of power consumption of blade rollerUsing the sensing technology to build the torque test system,build the cutter roller power consumption test bench,test the cutter roller torque,the cutter roller torque is reduced from 708.4N·m before optimization to 592N·m,the torque is reduced by 16.43%,and the simulation The test results are basically the same,verifying the accuracy of theoretical analysis and the rationality of the optimized design,and providing reference for field experiments.(5)Field performance testThe optimized roller assembly was assembled and tested in field.The indexes of straw returning rate,accumulated soil,surface smoothness,soil crushing rate and power consumption were tested.The indexes after optimization design were compared and analyzed.The results show that the soil in front of the optimized machine is obviously reduced,the straw returning rate and the stability of tillage depth are not significantly different,and the power consumption of the machine is reduced by 20.76%.The rationality and scientificity of the optimi zed design are verified,and the accuracy of the simulation test and the bench test are verified.