Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


PathakS.the (final).pdf (1.29 MB)

ETD Abstract Container

Abstract Header

A Dynamic Model of the Magnetic Head Slider with Contact and Off-Track Motion Due to a Thermally Actuated Protrusion or a Moving Bump Involving Intermolecular Forces

Pathak, Saurabh
http://rave.ohiolink.edu/etdc/view?acc_num=akron1468408012

Abstract Details

2016, Master of Science, University of Akron, Mechanical Engineering.
As the storage capacity of a given size of the hard disk drive continues to increase, the corresponding increase in the data storage density demands further reduction of the nano-scale gap (flying height) between the magnetic read/write head and the magnetic disk. In high-density magnetic recording, there can exist intermittent contact, and detection of contact also constitutes a necessary step in the process of thermal flying-height control. To further understand the head-disk contact phenomena, a computationally efficient five-degree-of-freedom dynamic model was developed to simulate the motion of a magnetic head slider under the conditions of moving-bump collision and of contact due to an expanding protrusion on the slider for thermal flying-height control, with consideration of intermolecular (interatomic) forces. An integrated formulation for the Lennard-Jones potential including effects of the van der Waals forces was used to characterize the intermolecular forces between the magnetic disk and the magnetic head slider. This dynamic model was based on a stiffness matrix formulation involving the pitch angle, roll angle, height of the slider center of mass, the cross-track displacement of the slider and the cross-track displacement of the actuator arm, with a stiffness matrix obtained by combining those of the suspension and the air bearing. To improve the computational efficiency in calculating the resultant force and moments, the integration of the intermolecular forces was separated into a part with analytical and semi-analytical integration over the smooth pad surface of the slider and another part of numerical integration in a small local region in the vicinity of a moving bump, which, in practice, could be a defect bump such as an adhered particle, or a laser bump usable in tests as a standard object with a known height. Compared to numerical results obtained without considering the intermolecular forces, these forces change the posture or attitude of the slider just before contact to create a slightly earlier contact when a moving bump on the disk tends to collide with the slider. This model was also used to simulate a stationary bump with an expanding bump height and with a zero lateral velocity so as to characterize an expanding protrusion on the slider surface in the active thermal actuation process for adjusting the flying height; the thermal expansion-related parameters used in this model were close to those extracted from a previous relatively complete fluid/thermo-mechanical analysis. The off-track motion of the slider was substantially increased by the intermolecular forces through a longer duration of contact, allowing prolonged application of the friction force under nonzero skew conditions. The numerical results obtained in this study shed light in the understandings of the precise behavior of the slider before, at, and after the contact with a bump or a thermal protrusion.
Shao Wang, Dr. (Advisor)
Shing-Chung "Josh" Wong, Dr. (Committee Member)
Graham Kelly, Dr. (Committee Member)
90 p.
Mechanical Engineering
Intermolecular Forces, Head Disk Interface, Off-Track Motion, Thermally Actuated Stationary Bump

Recommended Citations

Citations

  • Pathak, S. (2016). A Dynamic Model of the Magnetic Head Slider with Contact and Off-Track Motion Due to a Thermally Actuated Protrusion or a Moving Bump Involving Intermolecular Forces [Master's thesis, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1468408012

    APA Style (7th edition)

  • Pathak, Saurabh. A Dynamic Model of the Magnetic Head Slider with Contact and Off-Track Motion Due to a Thermally Actuated Protrusion or a Moving Bump Involving Intermolecular Forces. 2016. University of Akron, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1468408012.

    MLA Style (8th edition)

  • Pathak, Saurabh. "A Dynamic Model of the Magnetic Head Slider with Contact and Off-Track Motion Due to a Thermally Actuated Protrusion or a Moving Bump Involving Intermolecular Forces." Master's thesis, University of Akron, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1468408012

    Chicago Manual of Style (17th edition)

akron1468408012
702
© 2016, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.