Dynamical Simulation Of The Cassava Root’s Digging Mechanism

The main way of cassava root harvesting machinery is digging-elevating harvester,and the root digger is the critical component for loosening the soil.For now,the description of loosening the soil is not in particular,such as the interaction process between digger shovel and soil,the destruction of soil and the deformation and stress of root. Because the working mechanism of the digger shovel is the foundation for optimizing the structural and working parameters of it,so the dynamical simulation of the the cassava root’s digging mechanism has significant value.This paper firstly measuring the mechanics parameters of the cassava root and the soil.By using explicit dynamic simulation software ANSYS/LS-DYNA and a combination of Lagrange and smoothed particle hydrodynamics,the digging shovel-cassava-soil system dynamics simulation model has been established to simulate the process of digging soil loosening on the basis of the modified Mohr-Coulomb yield criterion.The precision of the simulation model was verified by physical experiment in the field.With help of simulation model,mechanism of shovel’s soil loosening, process of soil deformation, fracture and loosening, process of root’s stress changing were obtained at the micro level through numerical simulation.By single factor experiment,the effects of structural parameters of shovel tinepoint on the test index were studied.The results showed that the main reason of soil loosening is soil lifted by shovel blade resulting in bending and shearing fracture. Soil was lifted by shovel blade’s extrusion, resulting in root bending deformation. While shovel blade’s extrusion attains a certain value, the links between root and soil were destroyed. With the increasing of inclination angle and shovel width, traction resistance and loosening degree increased, but bending deformation and effective stress of root also increased, root can be broken easily, resulting in losses during harvest. With the increasing of wing angel, traction resistance and loosen effect decreased.