Research On The Wear Mechanism Of Cutting Teeth Based On Molecular Dynamics

The pick is a tool used in mining machinery to cut coal rock,which is widely used in various mining equipment.As a consumable part in mining machinery,the annual cost loss caused by the picking wear in our country is very huge.Although the hardness of coal is not enough to cause pick wear,the picks often encounter hard minerals such as pyrite and coal gangue during the mining process.Under the working conditions of direct contact with these hard minerals for a long time,the wear failure of the pick is very serious.Frequent picking failures seriously increase the mining cost on the mine,so it is of great significance for the study of the mechanism of pick wear.The existing experimental and simulation studies on pick wear are generally based on macroscopic perspective.The molecular dynamics simulation method is used to study the wear mechanism of hard mineral particles and picks under microscopic conditions.main tasks as follows:(1)The material crystal structure of the pick and hard minerals was modeled by silica and iron using the material calculation software Materials Studio.According to the crystal structure established in Materials Studio,in the large-scale molecular parallel operator LAMMPS a simulation model of single crystal wear of silica particles on iron metal was built.(2)The crystal structure change of the single crystal iron metal under the microscopic condition was analyzed by the central symmetry parameter method,and the reason for the large-scale slip in the specific direction inside the crystal was analyzed.The stress distribution characteristics of the iron metal in the wear process are analyzed by using the Villi stress,and the relationship between the stress concentration region and the shear slip region inside the iron metal is pointed out.(3)The distribution characteristics of iron metal in the wear process were analyzed,and the hardness of iron metal at different temperatures was tested.It was found that the hardness of iron metal decreased with the increase of temperature,and it was analyzed because of the crystal transfer at high temperature.Reduced by force.(4)The wear simulation model of polycrystalline iron was established by Voronoi polygon method,and the wear process of polycrystalline iron metal was analyzed from the perspective of structure,stress and temperature.In the comparative analysis with the wear process of single crystal iron,it is known that the polycrystalline iron metal has a smaller amount of wear under the same conditions than the single crystal iron metal due to the existence of grainboundaries.However,the heat generated by the polycrystalline iron metal wear process is larger than that of the single crystal iron metal,and the stress distribution inside the metal during wear is more dispersed than that of the single crystal iron metal.The paper has 42 pictures,5 tables,and 67 references.