Experimental Design And Discrete Element Simulation Of No-tillage Furrow Opener In South Paddy Field

The purpose of the no-tillage furrow opener is to make a neat furrow in the unplowed field after harvest in preparation for subsequent planting.As the main part of soil contact,furrow opener can directly disturb the soil and affect the quality of subsequent planting(sowing and seedling transplanting).Therefore,the research and design of the furrow opener are of great significance.In this paper,the southern no-tillage paddy field soil as the research object,through testing the basic parameters of soil and soil test design of three kinds of high moisture content and high stubble amount paddy field furrow opener.And the opener design by the discrete element simulation and field test the analysis and comparison of resistance in the process of the furrow opener,disturbance of soil and the surface roughness of after furrowing,it is proved that the designed furrow opener has good trench effect and the rationality of the simulation test results.The main contents are as follows:(1)The physical and mechanical properties of the soil in no-tillage paddy field in south China were measured and tested.The properties of soil and the parameters needed for simulation,such as soil moisture content,density and coefficient of internal friction,are obtained.The preliminary design idea of the furrow opener was obtained through soil soaking test and impact shear test.(2)Design the furrow opener.According to the idea of the soil test and the nature of southern paddy field and the agricultural demands,the design is a five-pointed star,is hexagonal star and slip into the soil of hexagonal sea star furrowing furrow opener,determined the structural parameters of the opener,movement parameter,the whole device,the copying device and the clogging device are designed.(3)Discrete element simulation and analysis are carried out for the furrow opener.(1)Firstly,a discrete element contact model suitable for paddy field surface clay and wet soil was established,and relevant simulation parameters of soil particles were set.(2)Three kinds of furrow opener comparison simulation test results show that: five-pointed star furrow opener achieve the best effect.The disturbance coefficient to the soil is small,and the surface roughness is good after the furrowing.After the furrowing process reaches a stable state,the horizontal resistance of the furrow opener is also the minimum,within the range of 20-25 N.(3)Take the furrow depth,forward speed,rotating speed as the factor,average groove resistance as the index to carry out the response surface test research of three factors and five levels,and use the designs-expert V8.0.6.1 software to process and analyze the simulation test data.The results show that there is interaction between test factors and indexes.The influence of single factor on average furrow opening resistance is extremely significant,and the significant order is: forward speed > rotating speed > furrow opening depth,and all of them are positively correlated with furrow opening resistance.The interaction between the forward speed and the rotating speed of the furrow opener has a significant influence on the average resistance of the furrow.When the furrow depth is constant,the resistance decreases with the acceleration of the forward speed and the decrease of the rotating speed of the furrow opener.The interaction between the other two factors has no significant influence on the index.(4)The solution of the optimal operating parameters of the furrow opener.The mathematical model and constraint conditions were established for the operating parameters of the furrow opener,and the optimization toolbox of Mat Lab software was used to solve the problem.The optimal operating parameters of the five-pointed star shaped furrow opener were determined as follows: the furrow depth was 64 mm,the forward speed was 1.8 m/s,and the rotating speed was 700 r/min.At this time,the average furrow resistance of the furrow opener was 24 N.(4)Field experiments were carried out on the furrow opener,and the maximum error between the field test data and the simulation test data was 18.3%,which verified the rationality of the simulation results and provided a new and efficient method for the structural design and operation parameter optimization of the furrow opener.In the field experiment,the furrow opened by furrow opener is narrow and obvious,which achieves the effect of local tillage and makes a good preparation for subsequent planting.In addition,the trenching process can reduce the resistance and soil disturbance.