Journal ArticleDOI
Vibration of Flex Circuits in Hard Disk Drives
TLDR
In this article, a flex circuit is modeled as a laminate of polyimide substrate, adhesive, and copper conductors and the model involves displacements of the flex circuit in the directions tangent and normal to the local equilibrium shape, and those motions couple with the arm's dynamics.Abstract:
A flex circuit connects the stationary electronic components in a hard disk drive to the rotating arm that carries the read/write heads and positions them above data tracks on the disk. Flex circuits are conventionally formed as a laminate of polyimide substrate, adhesive, and copper conductors. Deformation of a flex circuit is discussed in the context of the following stages: the initial unstressed shape, configurations in which stresses set and relax in response to elevated temperature, equilibrium, and small amplitude vibration. The model involves displacements of the flex circuit in the directions tangent and normal to the local equilibrium shape, and those motions couple with the arm's dynamics. Nonlinearity associated with finite curvature, partial elastic springback, and the arm 's geometry and inertia properties are incorporated within the vibration model to predict system-level natural frequencies, mode shapes, and coupling factors between the circuit and the arm. laboratory measurements using noncontact laser interferometry validate the model with respect to the circuit's shape, stiffness, restoring moment, and natural frequencies. The primary degrees of freedom for optimizing flex circuit design are the thicknesses of the individual layers within the circuit, free length, and the locations and slopes of the circuit's attachment points to the arm and electronics block. The model's predictions and trends developed from a case study in free length are discussed with a view toward reducing coupling between the circuit and arm in certain vibration modes.read more
Citations
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Journal ArticleDOI
Modeling and Measurement of a Bistable Beam in a Microelectromechanical System
Matthew R. W. Brake,Michael S. Baker,Nathan W. Moore,D A Crowson,John Anthony Mitchell,Jack E. Houston +5 more
TL;DR: In this paper, a step Euler-Bernoulli beam and a large deformation model were developed to model the force-deflection relationship of bistable mechanisms in microelectromechanical systems.
Journal ArticleDOI
Hard disk drive seek-arrival vibration reduction with parametric damped flexible printed circuits
TL;DR: In this article, a vibration damping approach to reduce flex cable related seek-arrival dynamics in a state-of-the-art magnetic disk storage drive has been proposed.
Journal ArticleDOI
Modeling and Analysis of Piezo-Elastica Energy Harvester in Computer Hard Disk Drives
TL;DR: In this article, a coupled piezo-elastic model is developed for the harvester with focus given to understand piezoelectricity generated by its PVDF layer over its underlying largely deformed flex cable elatica structure.
Journal ArticleDOI
Optimizing Vibration Isolation of Flex Circuits in Hard Disk Drives
TL;DR: In this paper, the results of parameter, optimization, and experimental studies are discussed with a view toward improving isolation of the arm from vibration of the flex circuit in one or several modes Particularly for the mechanism's odd modes, the free length and the relative attachment angle between the arm's centerline and the circuit can each be chosen to significantly reduce vibration transmission.
Journal ArticleDOI
Minimization of Flexible Cable Settling PES in High TPI Hard Disk Drives via Mechatronic Integration
TL;DR: It was found through the proposed process that the seek-settling flexible cable vibration can be minimized and even reduced to zero.
References
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TL;DR: Webb's work on elasticity as mentioned in this paper is the outcome of a suggestion made to me some years ago by Mr R. R. Webb that I should assist him in the preparation of a work on Elasticity.
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Non-linear vibration of a traveling tensioned beam
TL;DR: In this paper, a perturbation theory for the near-modal free vibration of a general gyroscopic system with weakly nonlinear stiffness and/or dissipation is derived through the asymptotic method of Krylov, Bogoliubov, and Mitropolsky.
Journal ArticleDOI
Planar vibration of an elastica arch : theory and experiment
TL;DR: In this article, a geometrically nonlinear rod theory is used to describe the planar bending and extension of the rod centerline, and numerical solutions for free vibration are determined using a variational formulation of the associated eigenvalue problem.