单颗磨粒磨削的分子动力学模拟

Molecular dynamics simulation of single abrasive grain grinding

为研究磨削加工过程中工件材料的去除机理,采用分子动力学方法模拟单颗磨粒磨削镍基合金的加工过程.利用多面体模板匹配的方法分析了单颗磨粒磨削过程中工件材料晶体结构的演变;研究了磨粒的磨削深度和速度对力、力比(切向力/法向力)和温度的影响规律及磨削力产生持续波动的原因;分析了磨削温度形成的内在机制,揭示了磨削界面热量产生的机理.结果表明:在磨削过程中,工件材料的初始面心立方结构主要转变为非晶结构和密排六方结构,少部分转变为体心立方结构;磨削力和力比随磨削深度的增加而增大,磨削速度对力和力比的影响较小,磨削温度随磨削深度和速度的增大而增大;在单颗磨粒磨削过程中,磨削热的主要来源是工件材料所发生的剧烈晶格变形,其次是磨粒与工件材料之间的摩擦.

In order to study the removal mechanism of workpiece materials during the grinding process,molecular dynamics was used to simulate the grinding process of nickel-based alloys with single abrasive grain.The PTM method was used to analyze the evolution of the crystal structure of the workpiece material during the grinding process of single abrasive grain;the influence of the grinding depth and speed of the abrasive grain on the force,force ratio(tangential force/normal force)and temperature,as well as the reasons for the continuous fluctuation of the grinding force were investigated.The internal generating mechanism of grinding temperature was analyzed,and the heat generating mechanism on the grinding interface was revealed.The results show that the initial FCC lattice structure of the workpiece material is mainly transformed into amorphous structure and HCP structure during the grinding process,and a small part is transformed into BCC structure.The grinding force and grinding force ratio increase with the increasing grinding depth.Grinding speed has little influence on the grinding force and grinding force ratio.Grinding temperature increases with the increase of grinding speed and grinding depth.During the grinding process of the single abrasive grain,the main source of grinding heat is from the intense lattice deformation of the workpiece material,followed by the friction between the abrasive grain and the workpiece material.