磨粒建模方法与切削过程仿真研究

针对砂轮表面上磨粒形状不规则、尺寸不确定的几何特征,研究了模拟实际磨粒的几何建模方法。采用随机空间平面切分正六面体的方法构建了具有实际磨粒几何特征的不规则多面体结构磨粒。基于LS-DYNA软件,采用流固耦合有限元法模拟了不规则多面体结构磨粒的切削过程。分析切削过程中工件材料的应力分布规律与切削变形规律,得出结论:工件材料的加工应力主要集中在与磨粒切削刃及棱角接触的区域;切屑沿磨粒挤压前面向上流动,并于挤压面法向方向上流出;磨粒挤压前角的增大有利于切屑的形成。利用陶瓷立方氮化硼(CBN)砂块进行了磨粒划擦试验,试验结果证实了磨粒切削仿真结果的准确性。

Study on Modeling and Cutting Simulation of Abrasive Grains

A modeling method of abrasive grains is studied in this paper taking into consideration their irregular geometry and inconsistent size. Abrasive grains in the shape of irregular polyhedrons are modeled by cutting regular hexahedrons with random space planes.Their geometric features are similar to those observed in natural abrasive grains. Based on the LS-DYNA software, the cutting process of irregular polyhedral abrasive grains is simulated by the fluid-solid interaction method. According to the stress distribution and deformation law of workpiece materials, it can be seen that the machining stresses of a workpiece material mainly concentrate on the areas which are in contact with the cutting edges and cutting points of the abrasive grains. Chips flow upward along the extrusion face of the abrasive grains, and finally flow out in the normal direction. An increase of the rake angle of abrasive grains is helpful to chip formation. Scratching processes of abrasive grains are experimented by vitrified bonded CBN blocks. The validity of the simulation is verified by experiment results.