| In recent years,bionics has been applied more and more widely in engineering technology,and has been applied to the optimization of soil tillage components in agricultural machinery.As an important conservation tillage technology,subsoil can effectively improve soil compaction and increase crop yield and income.It has been widely used all over the world.With the increase of tillage depth and tillage speed,it will cause problems such as high working resistance,energy loss and operation efficiency reduction.Therefore,this paper takes the sandfish(Scincus scincus)as the bionic prototype,using DEM simulated the motion of its special movement,to reduce the resistance of agricultural machinery moving forward in soil.Use the image processing and reverse engineering method to extract its characteristic morphology,verify the drag reduction effect of the geometric structure obtained,and apply the obtained geometric structure characteristics to the design of bionic subsoiler.Discrete element method is used to simulate the interaction between bionic deep loose shovel and ordinary deep loose shovel and soil,and the accuracy of the discrete element model is verified by soil bin test.It provides theoretical basis and design basis for energy conservation and drag reduction of soil tillage components of agricultural machinery and tools.The research contents of this paper are as follows:(1)Analyzing the movement mode of sandfish,it was found that sandfish was mainly powered by the body and tail with large amplitude sinusoidal pendulum.Through its head,it broke through the ground instantly and drilled into the sand dunes within half a second.Through reverse engineering technology extracted the side profile of the head,and used image processing technology to extract the top view contour of the sandfish’s head.Curve fitting was performed by MATAB software to obtain the characteristic curve equation,the second derivative and curvature.(2)In EDEM,the ordinary subsoiler tine setting sinusoidal motion was compared with the linear motion,it was found that sinusoidal motion has drag reduction effect.By DEM-MBD coupling,the interaction between sand fish and particles in soil was simulated,which was similar to the actual situation.(3)Based on the characteristic curves bionic samples were designed,the bionic sample was compared with the ordinary sample,each sample was manufactured by a3 D printer.The penetration test was carried out by electronic servo universal testing machine.It was found that the trend of force-displacement curves in the experiment was consistent with that in the simulation,and the Pearson correlation between the simulation and experiment results was 0.9942,0.9931,0.9899,0.9886,respectively.The accuracy of discrete element model was verified by simulation.(4)Applied the obtained geometric structure characteristics to the design of bionic subsoiler.EDEM discrete element software was used to compare and simulate the operation process of bionic subsoiler and ordinary subsoiler,the draft resistance of subsoiler and particle movement were derived,to verify the reliability of discrete element method simulation and the drag reduction effect of bionic subsoiler.Through the analysis of soil particle velocity field and soil disturbance,it was found that the bionic subsoiler can change the flow direction of soil particles,disperses the accumulation effect of particles,reduces the soil disturbance,and thus had smaller draft resistance.(5)Processed bionic and ordinary subsoiler tines,and installed on the handle of subsoiler respectively.A comparative experiment was carried out in the soil bin to verify the consistency of the discrete element simulation and the actual experiment results,and the influence of the structure,forward speed,working depth and other factors on the tillage resistance of subsoiler was investigated.It was found that the greater the tillage depth and forward speed,the greater the draft resistance,and the highest drag reduction rate of the bionic subsoiler was 9.31%. |
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