磁头磁盘的接触碰撞及窝点与挠臂的微动磨损数值模拟

发布时间：2018-03-29 17:15

本文选题：磁头磁盘　切入点：窝点与挠臂　出处：《华南理工大学》2014年博士论文

【摘要】：信息技术的不断发展对信息存储容量及存储安全性能的要求越来越高。超高密度存储硬盘的出现，使得磁头越来越贴近磁盘盘面，目前使用的硬盘中磁头与磁盘之间的飞行高度仅为几个纳米左右。硬盘正常工作时磁头的加载、卸载、动态飞行及寻址等动作会引起窝点与挠臂发生微小相对位移，导致窝点与挠臂的微动磨损，破坏窝点与挠臂间的接触面，影响磁头浮块的动态飞行能力。窝点与挠臂之间的微动磨损还会产生磨削颗粒，这些颗粒散落在硬盘里，容易卷入磁头与磁盘之间的微小间隙引起接触碰撞，损坏磁头组件与盘面，造成永久的数据丢失。硬盘在受到外界激振力作用时，更容易引起磁头磁盘的剧烈碰撞，从而加剧窝点与挠臂之间的微动磨损。特别是当硬盘处于充氦环境中时，稀薄的氦气在磁头受到挠动时能提供的阻尼作用有限，相同的激振力作用下，磁头磁盘的接触碰撞力远远大于处于空气环境中的硬盘。目前针对磁头磁盘接触碰撞过程中引起的窝点与挠臂之间的微动磨损研究很少。结合悬架有限元模型、浮块与盘面间的动态气浮轴承模型以及磁头磁盘接触碰撞模型，研究了当磁头与磁盘发生接触碰撞时引起的窝点与挠臂之间的动态接触力变化，研究了材料属性对窝点与挠臂动态接触力的影响，模拟了硬盘工作状态下受外界干扰时磁头的动态响应，模拟了较为真实工作状态下窝点与挠臂的动态接触力，为窝点与挠臂间微动磨损数值模拟奠定了基础。在目前较为新兴的充氦硬盘技术中，提出了使用氦-空混合气体来代替纯氦的方法。研究了氦-空混合气体的物理性质，结合动态气浮轴承模型以及粗糙磁头磁盘接触碰撞模型研究了在不同氦气比例下，磁头的动态飞行性能和磁头与磁盘接触碰撞性能。该模拟计算中使用了较新的气浮面设计，通过有限单元法求解了复杂气浮面上各节点的飞行高度和气浮压强。研究了磁盘速度对50%充氦环境中磁头与磁盘接触碰撞的影响。研究发现，氦-空混合气体代替纯氦在冲击载荷下能提供较好的阻尼作用，减少磁头与磁盘间剧烈的接触碰撞。建立了适用于微纳米量级幅值运动的微动磨损实验平台，通过实验方法研究了窝点与挠臂在不同载荷下的微动磨损行为，比较了激光抛光工艺对窝点微动磨损性能的影响。通过力传感器和激光测振仪采集数据与处理，获得了摩擦力-位移微动图和摩擦系数随着微动循环次数增加而演变的结果；通过扫描电镜的测量，，计算并比较了抛光与非抛光窝点磨损体积。研究表明，载荷会引起微动磨损区域转变而导致不同的表面损伤机理；表面粗糙度在较小载荷时对磨损体积的影响可忽略不计，但在较大载荷和较长时间的微动磨损中，激光抛光窝点可以显著减小磨损体积；计算了窝点动态微动磨损系数，为后续的微动磨损模拟奠定了研究基础。建立了窝点与挠臂的二维微动磨损模型，应用了实验中获得的摩擦系数及动态磨损系数。采用了改进的Archard磨损方程递进地计算了窝点与挠臂的局部磨损深度，研究并确定了最优的微动循环增量步，极大的减少了模型计算时间。运用该模型预测了不同载荷和微动循环次数下窝点与挠臂的磨痕形貌、接触压强及应力分布等。通过跟实验结果比较，表明该二维模型预测趋势跟实验结果一致但是误差较大，因模型计算较快可以用来定性研究几何尺寸和材料属性对窝点与挠臂微动磨损性能的影响。在二维微动模型基础上，建立了窝点与挠臂的三维微动磨损模型。推导了适应于不同微动位移的局部磨损公式，提出了自适应动态微动循环增量步方法，使以往耗时较长的三维微动磨损模拟在普通计算机上得以实现。通过跟实验结果对比，表明三维模型能更准确地预测窝点与挠臂的微动磨损表面形貌，误差为8.5%。因此，窝点与挠臂的三维微动磨损模型可为悬架窝点与挠臂的研究设计工作提供重要的理论指导。
[Abstract]:The development of information technology on the safety of information storage and storage capacity of the increasingly high demand. The ultra high density storage disk, the disk head closer to the surface, the hard disk between the head and the flying height of only a few nanometers. The hard disk magnetic head loading, normal work unloading, dynamic such action will cause flight and addressing dens and the flexure of micro displacement, resulting in fretting wear and flexure failure dens, dens and contact surface of flexible arm between the dynamic flight capacity magnetic floating block. Between the dimple and the flexure of the fretting wear produces grinding particles, these particles scattered in the hard disk, easy to get caught up in the small gap between the head and the disk caused by collision, damage the head assembly with the disk, causing permanent loss of data. The hard disk under the outside force, more capacity Easy to cause the violent collision of the head disk, thereby increasing the fretting wear between the dimple and the flexure. Especially when the hard disk is in helium environment, thin helium at the head by damping deflection can provide is limited, the exciting force under the same head disk collision force is far greater than in touch with the air environment in the hard disk.
The head disk contact between the dimple and the flexure caused by collision in the process of fretting wear seldom investigated. Combined with the suspension of finite element model, dynamic model and floating air bearing block between the disk and the head disk contact model of dynamic contact force between the slider and disk dens caused when contact happened during collision and torsion arm changes, to study the influence of material properties on the dynamic contact force of the flexible arm and dens, simulating dynamic hard working state interference when head response, simulation of dynamic contact force of dimple and flexible arm more real working conditions, laid the foundation for the dimple and the flexure between fretting wear numerical simulation.
In the helium filled hard disk technology is emerging, proposed to replace the pure helium helium - air mixed gas. The physical properties of helium - air mixed gas, combined with the dynamic air bearing model and rough head disk were investigated at different ratios of helium collision model, dynamic flight performance and magnetic head and disk contact the head performance. The simulation calculation is used in the design of new gas floatation, through the finite element method for solving the complex gas on the surface of each node and air pressure altitude. The effects of magnetic head and disk speed disk 50% helium filled environment contact. The study found that helium - air mixed gas instead of pure helium can provide better damping effect under impact load, reduce the head and disk between violent collision.
The fretting wear experiment platform is built for the micro nano motion amplitude, the fretting wear behavior of dimple and flexure under different loads is studied through the experimental method, the influence of laser polishing process on the fretting wear behavior of dens were compared. By means of force sensor and laser vibration measurement instrument data acquisition and processing, the friction force and displacement fretting maps and friction coefficient changes along with the results of fretting cycles; measured by scanning electron microscope, calculated and compared with the non polishing polishing dens wear volume. The results show that the load will cause the loss of area change caused the fretting wear damage mechanism of different surface; surface roughness in a low load effect on wear volume can be ignored, but in fretting wear large load and long time, laser polishing can significantly reduce the wear volume of dens dens; dynamic calculation The fretting wear coefficient has laid a foundation for the subsequent simulation of fretting wear.
A two-dimensional model for the fretting wear of dimple and flexible arm, application of the obtained dynamic friction coefficient and wear coefficient. The improved Archard equation to calculate the progressive wear depth of dimple and local wear of flexible arm, we determine the optimal cycle of micro increment, greatly reducing the calculation time. Using the model to predict the wear surface of different dimple and the flexure load and fretting cycles, contact pressure and stress distribution. By comparison with the experimental results, show that the two-dimensional model prediction with experimental results but the error is large, because the model can be used to study the rapid qualitative geometric dimensions and material properties of dimple and the flexure fretting wear properties of impact.
Based on a two-dimensional model, a three-dimensional model for the fretting wear of dimple and flexible arm. The local wear formula adapted to different displacement, the proposed adaptive dynamic micro circulation increment method, the time-consuming 3D fretting wear simulation in general computer implemented. By comparing with the experimental results. Show that the fretting wear surface morphology of the 3D model can more accurately predict the dens and flexible arm, so the error is 8.5%., dimple and the flexure 3D fretting wear model can provide an important theoretical guidance for the research and design work of suspension dimple and the flexure.

【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TH117.1

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