Abstract:The Geomagic studio 3D and SolidWorks software were used to 3D modeling the main lotus root of Elian No.5 with the elastic modulus,shear modulus,Poisson’s ratio and other intrinsic parameters obtained by uniaxial compression test and the contact parameters including the collision coefficient of restitution,static friction coefficient and rolling friction coefficient among lotus roots and between lotus roots and steel obtained by friction and collision test.The Hertz Mindlin with bonding model in EDEM simulation software was used to establish the discrete element model of main lotus root.The bending failure test of the main lotus root was conducted on the texture analyzer.Referring to the test results,the singlefactor and twofactor discrete element simulation tests of the bending failure of the main lotus root were carried out with normal stiffness per unit area,shear stiffness per unit area,critical normal stress and critical shear stress as the influencing factors.The results showed that the normal stiffness per unit area and the shear stiffness per unit area significantly affected the displacement and the first peak value when the first bending failure occurred,while the critical normal stress and the critical shear stress had no obvious effects on them.When the critical normal stress was 3.80 MPa and the critical shear stress was 3.12 MPa,the optimal solutions of the normal stiffness per unit area and the shear stiffness per unit area were obtained by steepest descent method to be 5.814×108 N/m3 and 3.450×108 N/m3,respectively.Based on this,the simulation peak value of the first bending failure of the main lotus root was 269.72 N and the displacement value was 7.14 mm.The relative errors of the simulation results and the measured results were 2.56% and 2.00%,respectively.The discrete element model of lotus root established will provide important reference for simulating the mechanical harvesting process of lotus root and effectively reducing the damage of lotus root.