Study On Mining Mechanism Of Panax Notoginseng Based On Discrete Element Method

Panax notoginseng is a famous Chinese herbal medicine.With the continuous increase of planting scale,the requirements for its harvest mechanization level are also higher and higher.However,there are still problems such as large traction resistance and high injury rate of Panax notoginseng.At present,the research on the harvest direction of Panax notoginseng at home and abroad is basically about the design of the whole machine and the design of excavating parts,but there is no in-depth research on the direction of excavating mechanism.This paper on the national natural science fund " Panax notoginseng harvest mechanization mining working mechanism and key technology research(51868023)",considering the notoginseng growth environment,set up soil-the roots-discrete element simulation model mining equipment system,using the numerical simulation analysis method,studied the soil and the coupling effect between mining parts,discusses the drag reduction approach,we design a mining device,test the digging shovel has good drag reduction effect.Specific research contents are as follows:(1)The soil parameters in the field of Panax notoginseng are calibrated,and the optimal value is obtained: the static friction factor is 0.98,the dynamic friction factor is 0.16,the JKR surface energy is 14.52J·m-2,and the recovery coefficient is 0.73.The soil groove model is generated,in which the proportion of single sphere particles is 33.1%,double sphere particles is 24.9%,and triple sphere particles is 42%.Three dimensional scanning and particle filling are carried out on the rhizomes of Panax notoginseng,and the discrete element system model of soil-rhizomes is established together with soil groove model.(2)This chapter refer to other rhizome crop excavation parts and combined with the special agronomic design of Panax notoginseng bionic excavation shovel,determine its structural parameters: total width 1300 mm,shovel body 1284 mm,side 7mm,shovel width 134 mm,shovel clearance 50 mm,shovel blade Angle of 60°,shovel body length 358 mm,the statics analysis,the maximum deformation is 1.7mm.Compared with the plane shovel with the same parameters,it is found that the drag reduction effect of the bionic shovel is better than that of the plane shovel under the same environment,and the drag reduction rate is 30.3%.(3)The established discrete element model is used to simulate and analyze the mining process.Based on the analysis of the whole movement and local movement law,the change law and flow condition of soil under excavation work are obtained,and the causes of choking and resistance are analyzed.The mechanical model of excavating shovel is established and analyzed.It is found that the main factors affecting the traction resistance of excavating shovel are the geometrical parameters,physical characteristic parameters and motion parameters of excavating shovel structure.By analyzing the movement process of rhizome of Panax notoginseng,it can be verified that its displacement law is affected by soil flow.(4)The bionic excavating shovel is processed and tested in the school.The experimental results show that the working resistance of the bionic excavating shovel is about 1896 N,and the working resistance of the combined excavating shovel with the same parameters and the same environment is about 2304 N,and the drag reduction rate is about 17.7%.The soil flow direction in the excavation process was compared with the simulation results,and the displacement path obtained was basically the same,which verified the accuracy of the simulation model.