Experimental Study On Impact Crushing And The Discrete Element Model Construction Of Granite Particles

The impact crushing of vertical shaft is an important part of the sand making process.Scholars at home and abroad have been working hard to improve the production of sand and reduce the energy consumption.For different sand making raw material,setting the proper combination of parameters for the crusher can improve the output and reduce energy consumption.If the impact crusher adopts a set of fixed parameters to handle all the material,then it will take longer and less effective in sand crushing process,setting reasonable to deal with raw materials of different sand crusher parameters,which will help improve the crushing efficiency,to achieve energy saving effect.Therefore,studying the relationship between the material and the key factors that influence the crushing effect,optimizing the structural parameters and production parameters of the broken main engine is of great significance for improving crushing efficiency and reducing energy consumption.s.Therefore,studying the relationship between of the material and various key factors that influence the crushing effect,optimizing the structure parameters and production parameters of the VSI have a great importance for improving the crushing efficiency and reducing the energy consumption.In this paper,based on the basic theory of active impact crushing,the key factors influencing the effect of sand making were investigated by using the technical scheme of experiment combined with simulation simulation.In the aspect of experiment,a single particle impact crushing experimental device was adopted,and the characterization parameters affecting the degree of fragmentation and grain shape were selected.Based on the regularities experiment of control variables,the influence rules of various parameters on rock fragmentation effect were analyzed and summarized.In terms of simulation,we use discrete element method and EDEM software to construct a cohesive model of granite with internal micro structural planes and cracks,and simulate the impact crushing process of materials.The main research contents are showed as the following aspects:(1)A experimental scheme of the single-particle impact crushing is designed,which including the acquisition of particle velocity and impact force.also,including the determination of the detection methods of the particle size.Also,throughout the experiment,the actual crushing ratio and sand forming rate were taken as the evaluation index of crushing degree,and the angularity,axial coefficient,roundness and overall contour coefficient were taken as the evaluation indexes of granule quality.Through the experimental methods of above,the influence law of the key parameters such as impact velocity,angle,particle size,rock morphology and particle material on rock crushing are obtained.(2)With the combination of SEM image detection and MATLAB image processing,the mesoscopic structure of rock surface is analyzed and the fissure rate for each observation point were extracted.Also,taking the fissure rate as the quantitative index,the relationship between the mesoscopic damage degree and fragmentation degrees of rock was analyzed.The experimental results showed that: with increasing fissure rate the degree of fragmentation of the particles increased.In other words,the initial meso-damage of the rock weakens the impact resistance inside the rock.(3)Based on the discrete element method and rock dynamic crushing theory,with the orthoclase,plagioclase,quartz and mica as the basic mineral particles,the coalescence square discrete element model was generated.Also,The impact curve of the cubic impact crushing experiment and the simulation is taken as the inspection index.Respectively,the crushing effect of the experiment and simulation with the different contact form between cubic ball and the iron plate of were compared,to verify the correctness of the particle cohesion model.This paper contributes to initiative impact crushing theory and further study of the structure parameters of the vertical shaft impact crusher,it is of preferably theoretical research value and practical value.