Design And Experiment Of Interactive Layered Subsoiler Based On Slide-cutting Principle

Subsoiling can achieve the purpose of breaking the bottom of the plow,retaining water in the soil,and increasing crop yield.In the Northeast straw retur ning field,the problems of large root-soil combination,high energy consumption,and large soil disturbance still existed in subsoiling operation,while the effects of soil disturbance and stubble-cutting affect the subsoiling operations quality,and the energy consumption determines the economic cost of subsoiling operations.The three are of great significance for the subsoiling study in straw returning.Therefore,in order to improve the performance of the subsoiling cutting stubble,reduce the energy consumption and the soil disturbance,an interactive layered subsoiler was designed in th is study.Theoretical analysis method,DEM,response surface method,field experiment method and multiple comparison method were comprehensively used to determine the structure parameters of the interactive layered subsoiler,to optimize its operating para meters,to analyze its operating performance comparatively,aiming at providing reference for the design and application of subsoilers in straw returning.The main contents of this study were as follows:(1)Material basic characteristics and discrete element methodThe sliding friction angle of the soil,corn straw and stubble in different height ranges under the corn straw returning were measured by the built material sliding friction test bench.In the mean time,the material moisture content,corn straw distribution,stubble structure size,soil density and internal friction angle were also measured.Based on the measured physical characteristics of soil,corn straw and stubble,a discrete element simulation model of soil-straw-stubble was established.(2)Design of the front shovel of interactive layered subsoilerAccording to the differences in the spatial distribution of soil,corn straw and stubble,the front shovel handle was divided into four sections for design.Through the sliding cutting theory and the sliding friction angle of soil,corn straw and stubble in different depth ranges,the four-stage shovel sliding-cutting angles and curve equation were obtained.The cutting edge angle,soil penetration angle,shovel thickness of the front shovel wer e also designed.Therefore,the front shovel with better sliding cutting and crushing performance was designed.(3)Design of the back shovel of interactive layered subsoiler and verifying experimentAccording to the soil particles backflow law during the fro nt shovel simulation process and the difference in the spatial distribution of soil and stubble,the interacti ve layered subsoiler rear shovel handle was divided into three sections for design.The line element method was used to fit the position and direction of the backflow of the soil particles to the maximum acceleration during the front shovel simulation process.After further optimization and Matlab fitting,the shovel handle curve equation of the back shovel sliding-cutting interactive section was obtained.The upper shovel handle and the lower shovel handle curve of the rear shovel were designed using the friction characteristics of the material and the sliding cutting theory.At the same time,the cutting edge angle,soil entry angle and shovel handle thickness of the rear shovel handle were designed.The distance between the front shovel and the back in the sliding-cutting interaction was determined according to the speed of the front shovel and the time for the soil particles to return to the maximum acceleration.Thus,a rear shovel that can form a sliding-cutting interaction with the front shovel be designed.The discrete elements were used to compare and analyze the interactive layered subsoiler and the front shovel.It was obtained that the diff erence in the direction of the maximum acceleration of the returning soil particles was small,which verified the rationality of the sliding cutting interactive design.The performance of interactive layered subsoiler,non-interactive layered subsoiler,ordinary layered subsoiler and ordinary single shovel were compared and analyzed by DEM.It was obtained that the interactive layered subsoiler has better cutting stubble,consumption and disturbance reduction performance.The finite element analysis of the interactive layered subsoiler using ABAQUS software shows that the strength of the subsoiler meets the needs.(4)Field optimization experiment of interactive layered subsoilerThe factors that affect the stubble-cutting effect,power consumption and soil disturbance of interactive layered subsoiling operation are forward speed,counterweight and straw coverage,which are got by the analysis of the layered subsoiling operation model under the corn straw returning.In order to study the influence of various f actors on the cutting stubble ratio,power consumption and soil disturbance,optimize the operating parameters of the interactive layered subsoiler,a three-factor,five-level,quadratic orthogonal rotation combination experiment was used for the interactive layered subsoiler with advance speed,counterweight,and straw coverage as experimental factors,and cutting stubble ratio,power consumption,and soil disturbance as evaluation index.The experimental data was processed and analyzed by Design-Expert 8.0.6.The simulation results showed that,as the forward speed was 2.81 km/h,the counterweight was 111.89kg,the straw cover was 0.81 kg/m~2,and the interactive layered subsoiler has the best performance.The optimal conditions of the interactive layered subsoiler were selected to carry out experiment to verify the optimization theory and basic operation performa nce.The results show that under the optimal conditions,the interactive layered subsoiler can meet the basic subsoiling needs,and the error between the experimental value and the theoretical value is less than 10%,and the optimization result is credible.(5)Field contrast experiment of interactive layered subsoilerIn order to compare and analyze the optimized design of interactive layered subsoi ler for comprehensive performance in field,the interactive layered subsoiler,non-interactive layered subsoiler,ordinary layered subsoiler,and ordinary single shovel were compared in field which the cutting stubble ratio,power consumption,soil disturbance amount,straw disturbance width,plow bottom soil compactness,soil broken rate and ditch width were used a s indicators.The SPSS software was used to analyze the variance and multiple comparisons of the operating performance of the four types of subsoilers under each index.The SPSS software was used to make multiple comparisons of the operating performance of the four types of subsoilers under each index.The results showed that the optimized design of the interactive layered subsoiler has the best comprehensive operation performance and can meet the needs of subsoiling operation under straw returning.At the same time,in the field experiment and the discrete element simulation,the size and trend of the four subsoilers cutting stubble,power consumption and soil disturbance are basically the same.It is known that the discrete element analysis is accurate.The interactive layered subsoiler designed in this study can enhance the performance of subsoiling operation and operation effect under corn straw returning.It provides a reference for the interactive design between the soil-contacting parts of agricultural machinery.At the same time,it can provide corresponding reference for the design and application of the subsoiling components in the corn straw returning of Northeast region.