Controlled Pyroshock Test Transients Can Be Used To Better Match Operational Shock Transients and Reduce Artificial Pyroshock Test Failures [Sides]

With the increased use of hard disk drives (HDDs) in mobile and consumer applications combined with the requirement of higher areal density, there is enhanced focus on reducing head disk spacing, and consequently there is higher susceptibility of slider/disk impact damage during HDD operation. To investigate this impact process, a dynamic elastic-plastic finite element model of a sphere (representing a slider corner) obliquely impacting a thin-film disk was created to study the effect of the slider corner radius and the impact velocity on critical contact parameters. To characterize the energy losses due to the operational shock impact damage, the coefficient of restitution for oblique elastic-plastic impact was studied using the finite element model. A modification to an existing physics-based elastic-plastic oblique impact coefficient of restitution model was proposed to accurately predict the energy losses for a rigid sphere impacting a half-space. The analytical model results compared favorably to the finite element results for the range from low impact angles (primarily normal impacts) to high impact angles (primarily tangential impacts).

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Microdrive operational and non-operational shock and vibration testing

Microsystem Technologies ◽

10.1007/s00542-006-0308-7 ◽

2006 ◽

Vol 13 (8-10) ◽

pp. 1015-1021 ◽

Cited By ~ 6

Author(s):

Bert Feliss ◽

Aravind N. Murthy ◽

Frank E. Talke

Keyword(s):

Vibration Testing ◽

Operational Shock

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Efficient Air Bearing Modeling for Operational Shock Analysis in 2.5-Inch HDD

2014 Conference on Information Storage and Processing Systems ◽

10.1115/isps2014-6959 ◽

2014 ◽

Author(s):

Kyoung-Su Park ◽

Geonyup Lim ◽

No-Cheol Park ◽

Young-Pil Park

Keyword(s):

Finite Element ◽

Element Model ◽

Air Bearing ◽

Contact Modeling ◽

Advanced Method ◽

Disk Contact ◽

Approach Method ◽

Bearing Stiffness ◽

Operational Shock ◽

Decoupled Method

As use of mobile computing devices has spread rapidly, it is very important to accurately analyze and predict anti-shock performance of the HDD system. In this paper, we proposed an efficient air bearing modeling method to analyze op-shock performance for the in 2.5-inch HDD system with ramp-disk contact behavior. We first constructed the decoupled approach method using linear air bearing springs in finite element method and used the Lagrange multiplier method for contact modeling between disk and ramp. With the constructed finite element model, the effect of linear air bearing stiffness was investigated in the decoupled method. We found that air bearing stiffness affects the behavior of the slider dominantly in the HDDs system with ramp-disk contact. Based on the numerical results, the advanced method able to efficiently reflect air bearing characteristics was proposed and evaluated.

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Operational Shock Response of Ultrathin Hard Disk Drives

2014 Conference on Information Storage and Processing Systems ◽

10.1115/isps2014-6962 ◽

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.

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