Design and test of a multi-edge toothed cutting device for membraneimpurity mixed material

As the existing residual film crushing device in Xinjiang cannot directly crush membrane-impurity mixed material,by analyzing the compressive and cutting force characteristics of residual film material layer and cotton stalk,the cutting conditions of mixed materials were obtained,and the method of cutting was determined.A multi-edge toothed cutters was created,and a cutting device was built.It was preliminarily determined that the number of teeth in the cutters was 8,the clearance between the teeth and between the tooth and fixed blade was 3 mm,the speed of the high-speed cutter was 800 r/min,and the speed difference between the high-and low-speed cutters was-300 r/min.Test results show that the ratio of residual film to total residual film sampling mass was(2.22±0.30)%,(19.19±2.02)%,(58.94±3.19)% and(20.65±2.05)%,respectively,when the maximum outer profile size in the range of[0,20)mm,[20,100)mm,[100,500)mm and[500,~)mm.The mass of cotton stalks with lengths of[0,50)mm,[50,100)mm and[100,~)mm accounted for(32.57±1.5)%,(27.77±1.3)%and(39.66±1.75)%,respectively,and the cutting power consumption was(85.41±15.63)kJ.The test results can provide a basis for the subsequent membrane-impurity mixed material cutting technology,as well as some guidance for the separation of it.

Calibration of the simulation parameters of the particulate materials in film mixed materials

In order to obtain accurate contact parameters of a particulate material in residual film mixture collected by cotton field machine in Xinjiang,the angle of repose test and inclined plane test were carried out.In the tests,the angles of repose of the particulate material with the water content of(6.26±1.5)%and(14.1±2.1)%were measured respectively,as well as the static sliding friction angle between the particulate material and the residual film.At the same time,the EDEM software was used to calibrate the coefficient of restitution,static friction coefficient and dynamic friction coefficient between the material and the film.Then,the second-order response model between contact parameters and the angle of repose and static sliding friction angle was constructed.In addition,the optimal contact parameters between the granular materials and the mulch were obtained by fitting the physical test data.The results indicated that the errors between the physical test results and the numerical simulation results are small.It was proved that the second-order response model could predict the repose angle of granular materials and the static sliding friction angle between granular materials and farmland film.This study could provide theoretical support for the subsequent model construction of the residual film mixture collected by the cotton field machine.

Calibration and test of the contact parameters for chopped cotton stems based on discrete element method

In view of the fact that the existing cotton stem simulation models are simplified and have a large discrepancy from the actual appearance and the contact parameters have not been calibrated.In this study,the simulation model and numerical simulation were established using the discrete element software EDEM.Then a second-order response model between contact parameters and repose angle had been constructed.The test result showed that the static friction coefficient,rolling friction coefficient,and coefficient of restitution between cotton stems were crucial factors affecting the repose angle.The determination coefficient corrected determination coefficient and p-value of the second-order response model were R^(2)=0.959,R^(2)_(adj)=0.921,and p<0.0001 respectively.The error values of the comparison between the simulation test results and the corresponding physical test values were all less than 10%,which showed that the model was reliable and had high interpretation and predictability,this study can provide a certain theoretical basis and data support for the setting of contact parameters in the data simulation of cotton stem harvesting and processing,mechanically-harvested film residue crushing and film stem separation,etc.

Cotton stalk restitution coefficient determination tests based on the binocular high-speed camera technology

The restitution coefficient(RC)of cotton stalks is an important elementary physical parameter that is required to establish the crushing mechanical model and research the film residue separation machinery.In this study,the calculation method of restitution coefficient considering the rotation motion of stalk-shaped agricultural materials was derived based on the principle of kinematics and the energy restitution coefficient method,and a test bench for measuring the RC was designed and built.The effects of collision material,moisture content,length,diameter,release height,and collision angle respectively on the RC were investigated by single-factor experiments and orthogonal experiments,and the regression models between influence factors and the RC were established.The results showed that Q235 showed the highest value of the RC,and it was followed by cotton stalks and soil lumps,sequentially.The RC of cotton stalks decreased with the increase of moisture content and diameter,while it increased at first and then decreased with the increase of length.As the release height was less than 500 mm,the RC increased with the increased release height.As the collision angle was less than 40°,the RC showed a linear increasing trend.The significance of the effects of factors on RC decreased with the following sequence:collision angle,length,release height,diameter,and moisture content.Length,collision angle,and release height were extremely significant.The contrast test results showed that the values based on Newton’s restitution coefficient method were smaller than that based on the energy restitution coefficient method.The verification test showed that the predicted rebound height of cotton stalks calculated based on the energy restitution coefficient method was closer to the actual rebound height,and the relative error was less than 5%.