Mechanical Analysis And Research On The Transport Process Of Granular Materials

Particle matter exists widely in nature,and has also been widely used in production and life.Particle matter is generally divided into granular media and powder.Granular media and powder are composed of a lot of particles.Particulate matter has strong interaction force,which belongs to the aggregated state material.The widely used concrete materials are made up by mixing the cement,sand and gravel(coarse aggregate),water,and many chemical additives,as a certain proportion.Aggregate in concrete is present in the form of a single solid particle,but changes into concrete after the configuration.Concrete is able to keep the same shape as brittle solid,and can also flow like a fluid,for example,concrete during pump truck transport process is flow.Due to the properties of both solid materials and fluid materials for concrete,when people use it in production and life,they meet a lot of challenges.On the one hand,in the concrete transportation project the concrete can be transported by pumping,on the other hand,its strength and durability need to be kept.Its physical properties are between solid and liquid.Such granular materials have not only the properties of solid and liquid,but also unique physical properties,which are different from solid and liquid.Therefore,it is particularly important to study the movement law of the transport process of particle matter.In this paper,based on the concrete pump truck material conveying process,the particle matter model was established.Then the mechanics model was established for the hard sphere particles.Based on the force chains between granular materials,the liquid bridge force between wet granular materials,particle flow and mechanical relations were investigated,and multi scale research framework was presented.The EDEM granular material mechanical analysis software was used to establish the particle model,particle factory,contact model,boundary conditions,simulation factory,etc.Two numerical examples are used to study the dynamic simulation of concrete pump truck conveying process,which expresses the movement law of granular materials directly.The velocity,displacement,quantity,the relationship between the force and the time,the movement track of the particle material and so on are obtained.This will provide a basis for the follow-up study of the simulation algorithm of particle material transport process,and the Visual Basic programming language was used to simulate the algorithm.The liquid bridge model of wet granular material is established and the liquid bridge is simulated as spring.The maximum coordination number of particles in the plane is 6,therefore,a micromechanical model of particle material flow is established,and the differential equation and the state equation of the particle materials are established.The Runge-Kutta numerical algorithm is used to solve the programming,which make the movement law of granular material solved more precisely.Based on the basic principle of the discrete element method,concrete pump truck transportation process,taking concrete particle matter as the research object,the contact mechanics model of particle model and wet particle material was established,and the dynamic simulation analysis was carried out by using the EDEM particle material mechanies analysis software.By using the numerical simulation method,differential equation and state equations were established,the movement rule of particulate matter was solved by using R-K algorithm.This research method is applied to a class of granular materials,which can not be solved by the theory,but can be realized through simulation.Such works bring meaningful academic value.Meanwhile,in practical engineering,this method can be used to simulate the actual working conditions,provide valuable parameters,and save cost and bring economic benefits.