Discrete element modelling of the yam root-soil complex and its verification

This paper constructs a discrete element simulation model of yam based on a bimodal model and uniform grid coordinates and performs parameter calibration on the simulation model based on three mechanical properties. The bonding parameters are: normal stiff-ness per unit area 8.0684 x 10(7) N center dot m(-3), shear stiffness per unit area 2.0314 x 10(7) N center dot m(-3), critical normal stress 1.2876 x 10(7) Pa and critical shear stress 8.9623 x 10(7) Pa. Using the root-soil complex shear test, based on the grey correlation analysis method, a root morphology index with the greatest correlation with the maximum shear force of the yam root-soil complex was obtained. The factor that has the greatest influence on the maximum shear force of the root-soil complex is the total surface area of the root, the correlation degree is 0.77. The root-soil complex bond parameters are as follows: normal stiffness per unit area 5.203 3 x 10(5) N center dot m(-3), shear stiffness per unit area 2.493 8 x 10(6) N center dot m(-3), the critical normal stress 1 x 10(5) Pa and the critical shear stress 5.319 0 x 10(5) Pa. The accuracy of the simulation model of the yam root-soil complex was verified by comparing the simulation test with the physical test. The relative error of the axial compression rupture pressure value of the yam root-soil complex simulation test and the physical test is 6.63%, the relative error of the displacement value is 8.83%, the relative error of the radial compression rupture pressure value is 6.83%, and the relative error of the displacement value is 6.38%. (c) 2022 IAgrE. Published by Elsevier Ltd. All rights reserved.