Simulation and measurement of a head-disk collision in magnetic data storage. (General Developments).
NIST has successfully developed an experimental technique and a numerical model to study the dynamic behavior of a head colliding with a disk. In the theoretical part of the study, a three-dimensional finite-element model was constructed to represent the overcoat, media and substrate, as well as a two-mass system, to represent the air-bearing slider. After solving the initial value problem, the model is capable of predicting the contact duration/frequency, contact forces, maximum penetration, energy dissipation and partition and underlying stress and deformation field for a given layered structure of the hard disk, asperity size and disk rotational speed.
In the experimental part of the study, a one-pass, high-speed impact test instrument and test method to evaluate materials responses on a hard disk surface have been developed. The basic concept is to artificially create a ridge (500 am to 2000 nm height and 0.002[degrees] to 0.010 angle of incline) on the disk surface by controlled scratching on the substrate side of the disk to create a ridge on the top surface with its multilayer intact. A 3 mm-diameter ruby ball collides with the ridge at 7200 rpm rotational speed. The impact force is measured with an acoustic emission sensor and the deformation volume is obtained with an AFM.
The bench test and the simulation model lead toward the goal of providing the necessary tools to optimize materials, lubricants, and mechanical design for future high-density storage technology.
CONTACT: Tze-jer Chuang, (301) 975-5773; firstname.lastname@example.org or Stephen Hsu, (301) 975-6125; email@example.com.
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|Publication:||Journal of Research of the National Institute of Standards and Technology|
|Article Type:||Brief Article|
|Date:||Jan 1, 2003|
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