Plane strain sliding contact of multilayer magnetic storage thin-films using the finite element method

Katta, Raja R.; Nunez, Emerson Escobar; Polycarpou, Andreas A.; Lee, Sung-Chang

doi:10.1007/s00542-009-0859-5

Cited by 17 publications

(7 citation statements)

References 26 publications

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“…While the steady-state value of the shear traction might be within the limits required to avoid plastic deformation in the DLC layer, the large variation due to vibrations after TD, as shown in figure 16(b), could cause damage to the disk. Specifically, the hardness of DLC is taken to be approximately equal to 1.8 times its yield strength [27], so its yield strength which is calculated to be 7.2 GPa, is larger than the maximum shear traction of 6.69 GPa at 12.2 nm of actuation as shown in figure 16(a).…”

Section: Assessment Of Contact Severitymentioning

confidence: 99%

Head-disk interface nanotribology for Tbit/inch² recording densities: near-contact and contact recording

Vakis

Polycarpou

2010

J. Phys. D: Appl. Phys.

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In the effort to achieve Tbit/inch2 recording densities, thermal fly-height control (TFC) nanotechnology was developed to effectively reduce the clearance (which is of the order of a few nanometres) at the head-disk interface (HDI) of hard-disk drives. In this work, we present a model of the HDI that can predict the dynamic flying and nanotribological contacting behaviour, allowing for accurate predictions and characterization of the operating regime as a function of TFC actuation. A geometric model for TFC is presented and an improved definition of contact at the interface is developed in the presence of nanoscale topographical roughness and dynamic microwaviness. A new methodology is proposed for the calculation of the nominal area of contact, which affects both near- and at-contact behaviour, while the stiffening of the air bearing force with TFC actuation is also accounted for. Slider behaviour is analysed by quantifying the approach, jump-to-contact, lubricant and solid contact regimes of operation and identifying the critical and optimum TFC actuations. The feasibility of near-contact, light molecularly thin lubricant contact versus solid contact recording is explored under the effect of the interfacial forces and stresses present at the HDI. The clearance and the state of vibrations are analysed and design guidelines are proposed for improved performance.

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Section: Assessment Of Contact Severitymentioning

confidence: 99%

Head-disk interface nanotribology for Tbit/inch² recording densities: near-contact and contact recording

Vakis

Polycarpou

2010

J. Phys. D: Appl. Phys.

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“…The steady state average value of the shear traction at a TFC actuation of 13 nm is 6.64 GPa. This is smaller than the yield strength of DLC, which can be calculated from its hardness to be 7.2 GPa (Katta et al 2009). The average steady state mean pressure for the same actuation is 4.88 GPa and is smaller than the DLC hardness of 13 GPa.…”

Section: Flyability Results For the Optimized Designmentioning

confidence: 99%

Optimization of thermal fly-height control slider geometry for Tbit/in2 recording

Vakis

Polycarpou

2010

Microsyst Technol

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Magnetic storage advances including thermal fly-height control (TFC) technology were able to reduce the clearance between the read/write elements of the slider and the disk surface to increase the recording density of hard disk drives without compromising the stability of the head-disk interface (HDI). Sliders employing TFC technology are designed for flying recording and can yield clearances of few nanometers. However, it is estimated that TFC technology alone cannot provide the even smaller clearances necessary to achieve Tbit/in 2 recording densities primarily due to the presence of instability-inducing vibrations at the HDI. In this work we perform optimization of the geometry of TFC technology sliders to achieve extremely high-density recording. We propose a flyability parameter coupled with a dynamic, contact mechanicsbased friction model of the HDI that accounts for TFC geometry and its influence on the HDI dynamics. Optimization results are analyzed and an operating actuation range is identified that can yield Tbit/in 2 recording densities with Angstrom-level clearance and minimized vibrations while also accounting for manufacturing and operational tolerances. This allows for light (lubricant) contact or 'surfing' recording. The proposed methodology can be used to reduce wear at the interface and investigate the feasibility of contact recoding.

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“…The study of the configuration that optimises the performance of the layered system to better accommodate contact load is a subject of interest [1,2] considering the cracking and damage modes that affect the contact fatigue life. With analytical solutions lacking even for homogeneous materials under contact load, various specialised numerical methods were developed in computational contact mechanics, seeking numerical solutions for the contact area, deformation and stresses arising in the contacting bodies: (a) the finite element method [3][4][5][6][7][8], (b) the boundary element method [9], (c) the equivalent inclusion method [10][11][12], and (d) the semi-analytical method (SAM) [13][14][15][16][17][18][19][20][21][22]. The latter is particularly efficient when coupled with Fourier transform algorithms that provide means for rapid calculation of convolution products, by converting the tedious integration operation from the problem space domain, into element-wise multiplication in an associated frequency domain.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Tri-Layered Materials Under Contact Load

Spinu¹

2021

IJMMT

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Various biomedical components, such as dental crowns and hip prostheses, data processing devices, and other numerous mechanical components that transmit load through a mechanical contact, may benefit from a tri-layer design. The coating may be optimized for wear protection and corrosion prevention, whereas the intermediate layer provides increased adhesion between the outer layer and the substrate, and confines the crack propagation. The solution to the contact problem involving tri-layered materials can be pursued numerically with the finite element or the boundary element methods, but semi-analytical techniques benefitting from the efficiency of the fast Fourier transform (FFT) technique have also been successfully applied. At the heart of the FFT-assisted approach lie the frequency response functions (FRFs), which are analytical solutions for fundamental problems of elasticity such as the Boussinesq and Cerruti problems, but expressed in the frequency domain. Considering recent efforts and results in application of FFT to convolution calculations in contact problems, the displacement arising in a tri-layer configuration is computed in the frequency domain, and the contact problem is subsequently solved in the space domain using a state-of-the-art algorithm based on the conjugate gradient method. The method relies on the FRFs derived in the literature for tri-layered materials, and the efficiency and accuracy of computations in the frequency domain is assured by using the Discrete Convolution Fast Fourier Technique (DCFFT) with influence coefficients derived from the FRFs. The computer program reproduces well-known results for bi-layered materials. Numerical simulations are performed for various configurations in which the elastic properties of the layers, as well as the frictional coefficient, are varied. By using the newly advanced simulation technique, design recommendations may be advanced for the optimal configuration of tri-layered materials under contact load.

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Plane strain sliding contact of multilayer magnetic storage thin-films using the finite element method

Cited by 17 publications

References 26 publications

Head-disk interface nanotribology for Tbit/inch² recording densities: near-contact and contact recording

Head-disk interface nanotribology for Tbit/inch² recording densities: near-contact and contact recording

Optimization of thermal fly-height control slider geometry for Tbit/in2 recording

Numerical Simulation of Tri-Layered Materials Under Contact Load

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Plane strain sliding contact of multilayer magnetic storage thin-films using the finite element method

Cited by 17 publications

References 26 publications

Head-disk interface nanotribology for Tbit/inch2 recording densities: near-contact and contact recording

Head-disk interface nanotribology for Tbit/inch2 recording densities: near-contact and contact recording

Optimization of thermal fly-height control slider geometry for Tbit/in2 recording

Numerical Simulation of Tri-Layered Materials Under Contact Load

Contact Info

Product

Resources

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Head-disk interface nanotribology for Tbit/inch² recording densities: near-contact and contact recording

Head-disk interface nanotribology for Tbit/inch² recording densities: near-contact and contact recording