Study On FEM-Based Incising Mechanism Of Saw-Tooth Type Cutter For Arundo Donax L.

Crop stalk is an important biological resource of the crop production system, whichcan be divided into two categories as high thick stalk and dwarf small stalk. Because ofbiological characteristics and growth mechanism of the high thick stalk crops is specially,its material resources yield significantly higher than that of small stalk crops. The highthick stalk is so hardness and stiffness that hardly to manual harvesting. There is notsuitable reaping machine until now, the research of its mechanized harvesting equipmenthas important practical significance. Literature shows that previous studies focus on thecut for harvesters working principle and structural parameters, no in-depth study on thestalk cutting process under the elastic and plastic stress and strain and other physicalphenomena. This thesis based on Arundo donax L. reaping machine which developed byCollege of Engineering Arundo donax L. mechanization harvesting group of HuazhongAgricultural University, through theoretical analysis and experimental, dynamicsimulation Arundo donax L. cutting process by finite element numerical simulationtechnologies, research cutting law of Arundo donax L. reaping machine to providetechnical support for Arundo donax L. mechanization harvesting and high thick stalkcrops mechanized harvesting equipment and development for new research methods andtheories, which is important theoretical and practical value. The main contents include:(1) Test measurement and analysis geometric parameters and physical mechanicalparameters of bottom stalk of Arundo donax L. in harvest period. Test measurement thatthe average stalk section spacing, diameter, thickness and other sections separatedgeometric parameters; moisture content in 11.4%-17.8% context, density 0.55g/cm3;longitudinal tensile, compression, bending stress and the destruction of elastic modulus.Analysis of test shows that Arundo donax L. is nonlinear fracture, transversely isotropic.Understand 12 elastic characteristics constant and the equation of Arundo donax L.flexibility matrix constant.(2) Theoretical analysis, high-speed photography and finite element methods wereapplied in the thesis. There analyzed the cutting process, confirmed numerical simulationalgorithm for the cutting process, established simulated model. Main include that dividedthe cutting process into three stages, analyzed force of cut in three stages; set up Arundodonax L. material elasticity coefficient matrix and elastoplastic material constitutiveequation based on miss von and yield criteria; got cutting model and used to solve thefinite element model of the K file based ANSYS-DYNA. The results revealed the law of Arundo donax L. cutting process, established Explicit Dynamics finite elementsimulation model of Arundo donax L. cutting process,(3)Carry up tests of Arundo donax L. cutting dynamic simulation and certification,identified certain conditions-chain serrated cutting operating parameters for the optimalcombination. The results show model based on the ANSYS-DYNA cutting is effective,this method is feasible. Through digital simulation and test verification to arrive atdifferent speeds serrated biggest stress, the maximum power, average power, Arundodonax L. single cut energy regression curve, the cutting device to determine when thefeed rate and cutting speed of the matching relations.