超精密加工机床空气静压主轴系统径向气膜刚度分子动力学模拟

Molecular dynamics simulation on radial gas film stiffness of aerostatic spindle system for ultra-precision machine tool

针对计算流体力学对超精密加工机床空气静压主轴系统进行动力学分析时的大跨尺度建模问题,该文基于分子动力学模拟基本原理和相似理论,利用LAMMPS开源软件和雷诺相似准则建立了超精密加工机床空气静压主轴系统的分子动力学微观模型。通过与文献算例比较验证了该模型的准确性,并进行了仿真分析。结果表明,在一定范围内,空气静压主轴径向气膜刚度随气膜厚度的增大而非线性减小,随主轴转速的增大而非线性增大,随进气压力的增大而非线性增大。

In view of the large-span scale problem of the computing model when dynamic analysis for the aerostatic spindle system of an ultra-precision machine tool is conducted by the computational fluid dynamics（ CFD）,based on the molecular dynamics simulation and similarity theory,the molecular dynamics microscopic model of the aerostatic spindle system for the ultra-precision machine is established by using an open source software LAMMPS and the Reynolds similarity criterion,and it is validated by the example of the reference. The results show that the radial gas film stiffness for the aerostatic spindle system decreases nonlinearly with the increase of the gas film thickness,increases nonlinearly with the increase of the spindle speed,and increases nonlinearly with increase of the inlet pressure in the certain range.