Study On The Law Of Particle Breakage Under Composite Loads Of Dynamic And Static

With the promotion and development of infrastructures in our country during recent years,gravel aggregate plays an important role as a building material.Natural gravel is nearly depleted after decades of mining.Manufactured gravel has become a major source of gravel aggregate.Driven by the rapid development of the gravel industry,the crushing equipment industry has also achieved rapid growth.At present,there is still some discrepancy between the study on the law of particle breakage and breakage mechanism and the existing manufacturing technology of crushing equipment,which will limit the overall improvement of the comprehensive performance of crushing equipment to some extent.Therefore,this thesis mainly focused on the regularity study of particle breakage and sought the theory of crushing for guiding industrial production and developing high-quality and green energy-conservation crushing equipment.The goal of this thesis is to construct a bonded particle model that reflects the physical and mechanical properties of rocks and finally conducting the study on the law of particle breakage under composite loads of dynamic and static.The main research contents of this thesis are as follows:First of all,a theoretical model for the study on the law of particle breakage under composite loads of dynamic and static was put forward by analyzing the crushing principle and method of a variety of crushing equipments and combining with the theory of crushing and the research status of crushing experiments.The model has five crushing factors including the moving speed of the moving plate,the curvature of the moving plate,the curvature of the fixed plate,the space of two plates,the initial radius of the particle.Secondly,the existing bonded particle model construction method was improved and a bonded particle model of uniaxial compression test specimen was constructed.Then,the uniaxial compression test of rock was used to match and check the parameters of the parallel bond and the bonded particle model.On the basis of it,the parameters of the parallel bond and the bonded particle model was verified with the particle unidirectional crushing test by the electronic universal material testing machine and discrete element method software.The results show that breakage behavior under unidirectional compression of the particle intercepted from the bonded particle model of the uniaxial compression test specimen is in consonance with the actual test.The bonded particle model of the uniaxial compression test specimen can reflect the physical properties of the rock.Finally,the tests of particle breakage with different crushing factors were carried out by the theoretical model of composite loads of dynamic and static.The tests were carried out to study the curves of the relationship between the moving speed of the moving plate,the curvature of the moving plate,the curvature of the fixed plate,the space of two plates,the initial radius of the particle and the crushing energy consumption,the crushed product,the degree of crushing which were defined in this thesis.The rules of particle breakage behavior under different levels of different crushing factors were also studied.Taking the minimum crushing energy consumption as the main evaluation index,the orthogonal test was carried out by selecting the optimal level from the tests before.The decreasing sequence and the significant effect analysis of all the crushing factors to the crushing evaluation indexes were studied by the range analysis and variance analysis.