SHOCK RESPONSE OF THE CLAMPED DISK IN SMALL FORM FACTOR HARD DISK DRIVE

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1592-1597 ◽  
Author(s):  
BIN GU ◽  
DONGWEI SHU ◽  
BAOJUN SHI ◽  
GUOXING LU
Keyword(s):  
Finite Element ◽  
Form Factor ◽  
Hard Disk Drive ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drive ◽  
Element Model ◽  
Small Form ◽  
Shock Response ◽  
Small Form Factor

As small form factor (one-inch and smaller) hard disk drives are widely used in portable consumer appliances and gadgets, their mechanical robustness is of greater concern. In the previous work, it is found that when the disk is more tightly clamped, it helps to decrease the shock response of the disk and then avoid the head slap. In this paper, the real boundary condition of the disk for a small form factor hard disk drive from Seagate is investigated numerically. The disk is clamped between the clamp and the hub. The shock response of the disk under a half-sine acceleration pulse is simulated by using the finite element method. In the finite element model, both contact between disk and clamp and contact between disk and hub are considered. According to the simulation results, how to decrease the shock response of the disk is suggested.

Shock Response of a Small Form Factor Hard Disk Drive With Air Bearing Interface Fully Coupled

2007 ◽  
Author(s):  
Jih-Ping Peng ◽  
Yu-Min Lee
Keyword(s):  
Form Factor ◽  
Hard Disk Drive ◽  
Degrees Of Freedom ◽  
Reynolds Equation ◽  
Hard Disk ◽  
Disk Drive ◽  
Air Bearing ◽  
Small Form ◽  
Shock Response ◽  
Small Form Factor

The present paper investigates the shock response of a small form factor hard disk drive (HDD). Both the air bearing and the entire HDD structure are considered in the model. The air bearing is described by the compressible Reynolds equation. The HDD structure is modeled by the finite element method. The Guyan reduction method is used to reduce the number of degrees of freedom to manageable size. CML Dynamic Simulator is used to solve the coupled structure equations and air bearing Reynolds equation.

Optimization of Air Bearing Contours for Shock Performance of a Hard Disk Drive

2003 ◽  
Author(s):  
Eric M. Jayson ◽  
Frank E. Talke
Keyword(s):  
Hard Disk Drive ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drive ◽  
Element Model ◽  
Time Dependent ◽  
Air Bearing ◽  
Disk Interface ◽  
Shock Response ◽  
Shock Event

Hard disk drives must be designed to withstand shock during operation. Large movements of the slider during shock impulse can cause reading and writing errors, track misregistration, or in extreme cases, damage to the magnetic material and loss of data. The design of the air bearing contour determines the steady state flying conditions of the slider as well as dynamic flying conditions, including shock response. In this paper a finite element model of the hard disk drive mechanical components was developed to determine the time dependent forces and moments applied to the slider during a shock event. The time dependent forces and moments are applied as external loads in a solution of the dynamic Reynolds equation to determine the slider response to a shock event. The genetic algorithm was then used to optimize the air bearing contour for optimum shock response while keeping the steady flying conditions constant. The results show substantial differences in the spacing modulation of the head/disk interface after a shock as a function of the design of the air bearing contour.

MODAL ANALYSIS AND DAMPING MEASUREMENT OF THE HEAD ARM ASSEMBLY OF A SMALL FORM FACTOR HARD DISK DRIVE

2010 ◽  
Vol 24 (01n02) ◽  
pp. 26-33
Author(s):  
B. J. SHI ◽  
B. GU ◽  
D. W. SHU ◽  
T. H. JIN
Keyword(s):  
Form Factor ◽  
Modal Analysis ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drive ◽  
Numerical Results ◽  
Fe Model ◽  
Small Form ◽  
Small Form Factor ◽  
Consumer Devices

As non-traditional applications of hard disk drives (HDDs) emerge, the interest in the effects of shock and vibration on small form factor (SFF) drives has come into currency due to the increasingly hostile environments encountered in the usage of the portable computer as well as the application in consumer devices. In this paper, the dynamic characteristics of an SFF drive were investigated using both experimental and numerical techniques, including modal analysis and damping measurement of the head arm assembly (HAA) of the drive. A finite element (FE) model of the HAA was created to perform numerical analysis. The FE model was verified and modified according to numerical results and experimental results. It is found that numerical results of the HAA in it free state and those in its preloading state coincide well with those of experiments, and/or those by other researchers.

Optimization of Air Bearing Contours for Shock Performance of a Hard Disk Drive

2005 ◽  
Vol 127 (4) ◽  
pp. 878-883 ◽  
Author(s):  
Eric M. Jayson ◽  
Frank E. Talke
Keyword(s):  
Hard Disk Drive ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drive ◽  
Element Model ◽  
Time Dependent ◽  
Air Bearing ◽  
Disk Interface ◽  
Shock Response ◽  
Shock Event

Hard disk drives must be designed to withstand shock during operation. Large movements of the slider during a shock impulse can cause reading and writing errors, track misregistration, or in extreme cases, damage to the magnetic material and loss of data. The design of the air bearing contour determines the steady-state flying conditions of the slider as well as dynamic flying conditions, including shock response. In this paper a finite element model of the hard disk drive mechanical components was developed to determine the time dependent forces and moments applied to the slider during a shock event. The time-dependent forces and moments are applied as external loads in a solution of the dynamic Reynolds equation to determine the slider response to a shock event. The genetic algorithm was then used to optimize the air bearing contour for optimum shock response while keeping the steady flying conditions constant. The results show substantial differences in the spacing modulation of the head-disk interface after a shock as a function of the design of the air bearing contour.

Numerical Simulation of Operational-Shock in Small Form Factor Hard Disk Drives

2006 ◽  
Vol 129 (1) ◽  
pp. 153-160 ◽  
Author(s):  
P. Bhargava ◽  
D. B. Bogy
Keyword(s):  
Form Factor ◽  
Hard Disk Drives ◽  
Strong Shock ◽  
Hard Disk ◽  
Air Bearing ◽  
Disk Drives ◽  
Small Form ◽  
Shock Response ◽  
Small Form Factor ◽  
Operational Shock

As nontraditional applications of hard disk drives emerge, their mechanical robustness during the operating state is of greater concern. Over the past few years, there has been an increasing application of small form factor (1in. and smaller) hard disk drives in portable consumer appliances and gadgets. A procedure for simulating the operational shock response of a disk-suspension-slider air bearing system is proposed in this paper. A coupled structural-fluid model is presented which can be used to obtain the dynamic response of the slider-suspension-disk system. A commercial program, ANSYS, is used for the finite element models of the suspension and the disk, while the CML dynamic air bearing code is used to concurrently solve the air bearing equations of the system. We obtain not only the responses of the structural components, but also the responses of the air bearing slider. The procedure is convenient for practical application as well as being highly accurate, since it implicitly solves the structural and air bearing problems simultaneously. It is used to simulate the shock response of a 1in. drive. The air bearing has different responses for upward and downward shocks (which are referred to as positive and negative shocks, respectively). For negative shocks, slider-disk contacts are observed to occur when a strong shock is applied, however, the air bearing does not collapse. For positive shocks, we observe a collapse of the air bearing when the shock is sufficiently strong, which is followed by severe contacts between the slider and the disk due to the “head-slap” phenomenon.

Modeling Airflow and Particle Trajectories Near the Head/Disk Interface Region of a Small Form Factor Hard Disk Drive Enclosure

2005 ◽  
Author(s):  
H. J. Goh ◽  
M. Damodaran ◽  
Q. Y. Ng
Keyword(s):  
Form Factor ◽  
Hard Disk Drive ◽  
Stokes Equations ◽  
Hard Disk ◽  
Disk Drive ◽  
Head Disk Interface ◽  
Particle Trajectories ◽  
Disk Interface ◽  
Small Form ◽  
Small Form Factor

Airflow characteristics and particle trajectories inside a small form factor hard disk drive (HDD) enclosure is modeled by creating a complex unstructured mesh around the various geometrical artifacts in the HDD enclosure using a commercial flow-solver which solves the incompressible Navier-Stokes Equations. From this model insight on the airflow characteristics in the vicinity of the slider could be obtained. The effect of the read/write head on the global flow field is also addressed for typical disk operation conditions. The computed airflow patterns are then used to predict particle trajectories in the vicinity of head/disk interface (HDI), the knowledge of which has relevance for tribological aspects connected with the HDI region. The effects of gravity and thermal gradients on the airflow characteristics within the HDD enclosure are also considered. Knowledge of particle trajectories and interaction provide useful guidelines for HDD design and filter locations. Depending on the types of particles, these are likely to be subjected to gravitational and thermophoretic forces, or inter particle interactions. Particles of different materials and sizes are used to evaluate the effects of these forces, which influence the particle trajectories.

Effect of Dimple Offset on the Operational Shock Performance of Small Form Factor Disk Drives

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Puneet Bhargava ◽  
David B. Bogy
Keyword(s):  
Form Factor ◽  
Hard Disk Drives ◽  
Leading Edge ◽  
Disk Drive ◽  
Air Bearing ◽  
Disk Drives ◽  
Small Form ◽  
Small Form Factor ◽  
Bearing Dynamics ◽  
Operational Shock

This paper discusses the effect of varying the suspension load dimple location on the shock robustness of small form factor hard disk drives. We use the CML shock simulator, which simulates the structural as well as the air bearing dynamics of the disk drive simultaneously. The location of the dimple is varied and simulations are run for various load positions on the back of the slider, while adjusting the pitch static attitude (PSA) and the roll static attitude (RSA) of the slider such that the flying attitude of the slider remains the same. We simulate shocks of 0.5 ms pulse width for a commercially available slider and suspension designs for a 1 in. drive. We observe that shock resistance is optimal when the dimple is offset toward the leading edge of the slider. This behavior is explained on the basis of a linearized air bearing model. It is also observed that moving the dimple too much toward the leading edge causes the mechanism of shock failure to change resulting in lower shock tolerances.

Scaling and Shock Response of Small Form Factor Disk Drives

2005 ◽  
Author(s):  
Jianfeng Xu ◽  
Frank E. Talke
Keyword(s):  
Form Factor ◽  
Hard Disk Drive ◽  
Dynamic Characteristics ◽  
Disk Drive ◽  
Disk Drives ◽  
Head Disk Interface ◽  
Static And Dynamic Characteristics ◽  
Disk Interface ◽  
Shock Response ◽  
Small Form Factor

The effect of miniaturization on the static and dynamic characteristics of hard disk drive suspensions and disks is investigated. Mechanical scaling of dimensions is discussed and the shock response of the head disk interface is evaluated as a function of the disk form factor.

Effects of Air Bearing Stiffness on a Hard Disk Drive Subject to Shock and Vibration

2003 ◽  
Vol 125 (2) ◽  
pp. 343-349 ◽  
Author(s):  
Eric M. Jayson ◽  
J. Murphy ◽  
P. W. Smith ◽  
Frank E. Talke
Keyword(s):  
Finite Element ◽  
Hard Disk Drive ◽  
Hard Disk ◽  
Disk Drive ◽  
Element Model ◽  
Air Bearing ◽  
Head Disk Interface ◽  
Disk Interface ◽  
Wide Range ◽  
Bearing Stiffness

A finite element model of a hard disk drive (HDD) is developed to investigate the transient response of an operational HDD subject to shock and vibration. The air bearing stiffness of the head disk interface is determined from a finite element solution of the Reynolds equation and approximated with linear springs. The structural response is analyzed for several types of sliders with a wide range of air bearing stiffness. Results show the response of the head-disk interface subject to shock and the modes excited by vertical and lateral vibrations of the HDD.

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