Study On Mechanical Properties And Cutting Simulation Of Mature Stalk Of JUNCAO

JUNCAO is a versatile herb which has great varieties and mainly used for cultivating mushrooms,lucidum,auricularia and other edible or medicinal fungi.With continuous and in-depth study in the recent thirty years,our country has made great improvement in the modified,cultivation and popularization of JUNCAO.Mechanized harvesting of JUNCAO had a direct promoting role in improving labor productivity,reducing production costs and improving resource utilization as constant enlargement of JUNCAO planting area.Mechanical properties of JUNCAO stem is the base for the establishment of the material model of JUNCAO stem,which is important parameter basis to develop efficient,low consumption stalk cutter,helps to reduce development costs and shorten the development cycle of agricultural machinery in the design phase.Therefore,this study used a universal testing machine to test JUNCAO stem by tension,compression,bending,orthogonal shocks,and obtained resistance strength,elastic modulus and other mechanical parameters of JUNCAO stem.In order to study cutting properties of JUNCAO,this paper had designed a reasonable cutter for JUNCAO harvesting,processed static and modal analysis on the cutting parts,established the finite element model of cutting process of JUNCAO stem and cutter,and researched on the relation between two factors of blade speed and stem diameter to the cutting performance of the blade.which provides the theoretical basis to design JUNCAO stem cutter and disintegrator.The main contents and conclusions are as follows:(1)The test on physical properties of different parts of Pennisetum sp stem.The results showed that with increasing height of Pennisetum sp stem,outer diameter,inner diameter,internode length had a linearly decreasing trend,the moisture content had an increasing trend,while the wall thickness did not change significantly.(2)Select mature stems of Pennisetum sp,Elephant grass,Pennisetum puerperium Schumab cv as experimental materials and take an orthogonal experiment with four factors and three levels,which obtained the tensile,compression,bending strength and elastic modulus and other mechanical parameters of JUNCAO stem.Then processed the data by using variance analysis.(3)Design a reasonable cutter for JUNCAO harvesting.The cutter parts were analyzed by ANSYS/Workbench for static and modal analysis.The results showed that the force on cutter parts subject during the cutting process was much slight than the cutter material itself yields limit,and the deformation was quite lightly,which met the cutting requirements of stiffness and strength.(4)Using ANSYS/LS-DYNA to accomplish dynamic Simulation and Analysis on the cutting process of JUNCAO stem.Study of the relation between two factors of blade speed and stem diameter to the cutting performance of the blade.The results showed that the maximum equivalent stress ?max is largest when the blade cut out stems during cutting process,meanwhile,the blade is more prone to performance failure.The slower the blade speed,the lighter the maximum equivalent stress ?max is,but if the speed is too fast,the cutter operating frequency is increased,it may cause resonance,exacerbating structural vibration,and then lead the cutter not to work.