Discrete Element Simulation Of Longitudinal Behavior Of Objects Moving Horizontally In A Granular System

The longitudinal behavior of objects moving horizontally in the granular system is a hot issue for scientists.According to the reports existed,objects dragged horizontally and uniformly can rise in the granular system.However,there is little discussion about how to achieve the sinking behavior of objects in the granular system.We found that there is a kind of lizard in the desert that can rise and sink in the desert by swinging their body.Inspired by this phenomenon,we mainly focused on the objects vibrating horizontally in the granular system,try to get conditions that can cause objects under horizontal motion to sink in the particle system.The simulation of this thesis is carried out by using three-dimensional discrete element numerical simulation program LIGGGHTS.Beginning with a simpler structure,we simulated the longitudinal behavior of a sphere moving horizontally in the granular system.It is found that the sphere in the granular system will rising when it is dragged at a constant speed,and the rising speed is affected by the drag speed and the density of the sphere.On the other hand,it is found that the sphere under horizontal vibration will rise or sink according to the vibration parameters.Then,taking the behavior of the sphere as a reference,the behavior of the cylinder vibrating horizontally in the granular system is studied,and the influence of the shape of the cylinder as well as the vibration parameters on its longitudinal motion is obtained.The results show that the direction and magnitude of the longitudinal velocity of the cylinder are affected by density and radius of the cylinder as well as the period and amplitude of vibration.According to the results,the expression of lift force of the cylinder vibrating in the granular system is obtained.In addition,the causes of different behaviors in the longitudinal direction of the cylinder vibrating in the granular system are analyzed,and the necessary conditions for it to sink are given.Finally,we analyzed the stress of the triangular prism dragged horizontally and uniformly in the particle system.Through the analysis,the effects of the inclination angle and the depth of the prism,and the speed of dragging on the longitudinal force of the prism are obtained.The conclusions of this thesis enrich the related theories of the particle dynamics,and explain the mechanism of the rise and sink behavior of the object moving horizontally in the granular system to a certain extent.