Numerical Analysis Of The Working Process And Friction Wear Of Micro Rotary Tiller Plough Coulters

Hilly and mountainous areas occupy a large part of the arable land area,in addition,the scale of agricultural operation in our country is family-oriented and requires small-sized machinery,which determines that the micro rotary tiller has become an important part of agricultural mechanization in China.The plough coulter is the main working part of the micro rotary tiller,and the wear of the blade edge induced by high-speed rotary plowing will seriously affect the service life of the plough coulter and the efficiency of the micro rotary tiller,therefore,the study of the wear of the plough coulter of the micro rotary tiller is a very practical subject on the road to the development of agricultural mechanization.In this study,on the basis of the analysis of the working process and wear form of the micro rotary tiller plough coulter,the finite element method is used to carry out kinetic simulation of the working process of the micro rotary tiller plough coulter cutting soil,the Archard wear formula applicable to the wear of the plough coulter cutting soil is deduced,the numerical analysis of the wear form of the micro rotary tiller plough coulter is carried out by writing the subroutine of UMESHMOTION.Validation of the results of the numerical analysis of wear was carried out in field tests.The main research contents and conclusions are as follows:（1）The motion,dynamic balance and force analysis of the combined plough coulter of the micro rotary tiller with 3 large curved blades and 2 small curved blades,the motion of the plough coulter is a vector synthesis of linear and rotary motion,and the trajectory of its tip is a pendulum line.The plough coulter plowing is mainly subject to the blade surface cutting soil resistance,normal and tangential resistance on the blade edge and the friction generated by the blade surface cutting soil,resulting in tool wear and power loss,through metallographic microscopy observation of the wear surface micro-morphology of the plough coulter,to determine the wear loss of the plough coulter wear efficiency is in the abrasive wear,corrosion wear and fatigue wear under the joint action of the composite wear type.（2）Based on the movement characteristics of the plough coulter of the micro rotary tiller and Druker-Prager soil ontological model,using finite element analysis software ABAQUS on the micro rotary tiller plough coulter plowing process to display dynamic simulation,analyze the deformation of soil in the process of the plough coulter cutting soil,the plough coulter plowing resistance and the change rule of contact stress.Simulation results show that the plough coulter cutting soil force has periodicity,the plough coulter in the forward speed of 1km/h,rotational speed of 425r/min and plowing depth of 10cm under the conditions of plowing the tip of the plow and the soil for a contact lasts for 0.022s,and the average contact stress in the process of contact with the soil is 2.522Mpa.（3）Comparing the wear calculation formulas commonly used in wear research,the Archard wear formula was selected as the basis for the construction of the mathematical model of plough coulter wear,and the constant K=1.75×10^-5 in the mathematical model of wear rate was determined by backpropagation using experimental and simulation data to establish a mathematical model based on the wear of plough coulter cutting soil.Data extraction scripts and subroutines of the simulation software ABAQUS were written to numerically analyze the frictional wear of the plough coulter tip.Numerical analysis of wear was carried out for 2 hours,3.5 hours,5 hours and 6 hours,and the results showed that the maximum wear areas were all concentrated in the junction zone of the rear blade surface and the tip of the plough coulter,with the maximum wear of 1.887mm,2.750mm,3.766mm and 4.359mm,respectively,and the tip of the plough coulter with the wear of 1.061mm,1.857mm,2.653mm,respectively,3.184mm.The experimental results show that the wear numerical analysis method proposed in this study has a good prediction of the wear amount of the plough coulter cutting soil within the same wear stage of the plough coulter.