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.

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.

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.

Operational shock response of ultrathin hard disk drives

2015 ◽  
Vol 21 (12) ◽  
pp. 2573-2579 ◽  
Author(s):  
Shengkai Yu ◽  
Jianqiang Mou ◽  
Wei Hua ◽  
Weidong Zhou ◽  
Chye Chin Tan
Keyword(s):  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drives ◽  
Shock Response ◽  
Operational Shock

Operational Shock Response of Ultrathin Hard Disk Drives

2014 ◽  
Author(s):  
Shengkai Yu ◽  
Jianqiang Mou ◽  
Wei Hua ◽  
Weidong Zhou ◽  
Chye Chin Tan
Keyword(s):  
Hard Disk Drives ◽  
Hard Disk ◽  
Element Model ◽  
System Level ◽  
Disk Drives ◽  
Disk System ◽  
Shock Response ◽  
Shock Simulation ◽  
Resistance Performance ◽  
Operational Shock

Operational shock is one of key challenges for designing the ultrathin mobile hard disk drives (HDDs) due to the reduced thickness of mechanical components and their stiffness. Some simplifications in the conventional methods for operational shock simulation are not valid. In this paper, a method for system level modelling and simulation of operational shock response of HDDs has been proposed by coupling the structural finite element model of the HDD and the air bearing model. The dynamic shock response of the head-disk system in a 5 mm ultrathin HDD design is investigated. The effects of drive base stiffness, disk-ramp contact, disk spinning and disk distortion have been studied. The results reveal that the drive base deformation and ramp contact are critical for the operational shock resistance performance of ultrathin drives.

Experimental and numerical investigation of shock response in 3.5 and 2.5 in. form factor hard disk drives

2006 ◽  
Vol 12 (12) ◽  
pp. 1109-1116 ◽  
Author(s):  
Aravind N. Murthy ◽  
Bert Feliss ◽  
Donald Gillis ◽  
Frank E. Talke
Keyword(s):  
Form Factor ◽  
Numerical Investigation ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drives ◽  
Shock Response

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.

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