计算机磁头/磁盘超薄气膜润滑稳定性

以任意拉森数的超薄气体润滑方程为基础,给出磁头刚体小扰动对空气轴承滑块 (ABS)气膜压强摄动方程。采用算子分裂法求解气膜压强和非结构三角网格的有限元法解压强摄动方程,得到气膜的刚度系数和阻尼系数矩阵。模态分析得到磁头气固耦合系统的固有频率,衰减率和振型。以Ω型磁头为例,分析了在不同气膜厚度和磁盘转速下的磁头稳定性。研究结果表明,磁头稳定性对气膜厚度很敏感,在小气膜厚度运行时,系统固有频率高,稳定性好;磁头升沉和纵倾运动的动力耦合,使磁头系统固有频率和衰减率降低,对稳定性不利;高转速的磁盘对磁头稳定性不利,但影响不大。

Stability Analysis of Ultra-Thin Gas Film of Magnetic Head-Disk Interface

We present a pressure perturbation equation of ultra thin gas film lubrication based on a generalized gas lubrication equation applicable to arbitrary Knudsen number. The film pressure of air bearing slider (ABS) is solved by operator splitting and finite element method. The pressure perturbation equation is solved by finite element method with unstructured triangle grids for film stiffness and damping coefficients. Modal analysis of coupled system of magnetic head and gas film is carried out to obtain natural frequencies, damping rates and mode shapes of the magnetic head vibrations. We also perform stability analysis of Ω type magnetic head. Numerical results indicate that the natural frequencies of the system are higher as the film thickness is smaller. It is also found that the natural frequencies and damping rate of the coupled vibration mode of heave and pitch motions are much lower than those of uncoupled modes. When the disk rotation speed increases, the stability of magnetic head is slightly worsened.