Numerical Simulation And Experimental Study On Soil Cutting By Rotary Tillage

The high energy consumption of rotary tillage is an urgent problem to be solved in farmland operations.The rotary tiller is the main working part of the rotary tiller,and most of the energy of the rotary tiller is used for cutting the soil by the rotary tiller.The shape and parameters of the rotary tiller blade directly affect the working quality and power consumption of the rotary tiller.This paper takes IT245 rotary tiller as the research object,establishes the mathematical equation of the rotary tiller,and calculates the theoretical specific work of cutting soil.Based on ANSYS/LS-DYNA software,the simulation model of rotary tillage and soil cutting was established,and the numerical simulation of the soil cutting process of rotary tiller was carried out.A set of rotary tiller torque measurement system was designed,and the accuracy of the simulation model was verified by soil trough test.According to the Box-Behnken test,the operating parameters of the rotary tiller were optimized,and 9 convex hull drag-reducing rotary tillers were designed,and the optimal operating parameters and the effect of the drag-reducing rotary tiller were verified by soil trough tests.The main research contents and conclusions are as follows:(1)Mathematical modeling and theoretical specific work analysis of rotary tiller blade surface.The operating parameters of the rotary tiller were analyzed,the mathematical equation of the rotary tiller surface was established,the numerical calculation was carried out based on MATLAB,and the calculation formula of the theoretical specific work of rotary tillage and soil cutting was derived.The results can basically correctly reflect the influence of the operating parameters on the work.(2)Establish and verify the finite element rotary tillage soil cutting model.Based on the Smooth Particle Hydrodynamics(SPH)method,a finite element model of rotary tillage and soil cutting was established,and the model was used to analyze the conditions of the forward speed of 0.6m/s,the rotation speed of the cutter roller of 200r/min and the tillage depth of 0.12 m.In the process of rotary plowing and cutting soil,the soil throwing speed is about 2m/s,the average forward resistance is 258.61 N,and the average torque is 59.65N·m.A torque measurement system was designed,and the soil tank test was carried out based on the system.The average torque of rotary tillage was 63.69 N m,which was only 6.34%worse than the simulation test,which verifies the correctness of the power consumption calculation of the simulation model for rotary tillage and soil cutting..(3)Optimization and verification of the operating parameters of the rotary tiller.The Box-Behnken test was used to simulate and analyze the effects of forward speed,cutter roller speed,and tillage depth on the specific work of rotary tillage.The results show that the forward speed is negatively correlated with the specific work of rotary tillage,the speed of the cutter roller is positively correlated with the specific work of rotary tillage,and the tillage depth has no significant effect on the specific work of rotary tillage.The optimal operating parameters were obtained: the forward speed was 0.7m/s,the rotation speed of the cutter roller was 200r/min,and the tillage depth was 0.12 m.The optimal operating parameters were verified,and the specific work of the optimal operating parameters was reduced by 10.53% compared with the working conditions of the forward speed of 0.6 m/s,the rotation speed of the cutter roller of 200 r/min and the tillage depth of 0.12 m.(4)Design and verification of the convex hull drag-reducing rotary blade.The convex hull structure of the head of the molting beetle can reduce the adhesion.Nine types of dragreducing rotary tillers with convex hulls on the surface are designed.The resistance reduction effect of the plough blade is found to be positively correlated with the convex hull size within a certain range,and negatively correlated with the convex hull interval.Using the No.8 drag-reducing rotary blade and carrying out the soil tank test,the torque is 20.16%lower than that of the national standard rotary blade.