Elastic-Plastic Finite Element Analysis for the Head-Disk Interface With Fractal Topography Description

2002 ◽  
Vol 124 (4) ◽  
pp. 775-784 ◽  
Author(s):  
K. Komvopoulos ◽  
N. Ye

An elastic-plastic contact analysis based on a finite element model and real surface topographies was performed to elucidate the evolution of deformation at the head-disk interface. The topographies of the head and disk surfaces were represented by an equivalent profile generated using a modified two-variable Weierstrass-Mandelbrot function, with fractal parameters determined from images of head and disk surfaces. A region of the equivalent rough surface profile was selected for analysis based on topography scale considerations and contact simulation results. The evolution of plasticity and the likelihood of cracking in the overcoat and the magnetic layer are interpreted in light of results for the subsurface von Mises equivalent stress, equivalent plastic strain, and maximum first principal stress. The finite element model provides insight into the elastic-plastic deformation behavior of the layered medium in terms of the thickness, mechanical properties, and residual stress in the carbon overcoat.

2014 ◽  
Vol 680 ◽  
pp. 249-253
Author(s):  
Zhang Qi Wang ◽  
Jun Li ◽  
Wen Gang Yang ◽  
Yong Feng Cheng

Strain clamp is an important connection device in guy tower. If the quality of the compression splicing position is unsatisfied, strain clamp tends to be damaged which may lead to the final collapse of a guy tower as well as huge economic lost. In this paper, stress distribution on the compressible tube and guy cable is analyzed by FEM, and a large equivalent stress of guy cable is applied to the compression splicing position. During this process, a finite element model of strain clamp is established for guy cables at compression splicing position, problems of elastic-plastic and contracting are studied and the whole compressing process of compressible position is simulated. The guy cable cracks easily at the position of compressible tube’s port, the inner part of the compressible tube has a larger equivalent stress than outside.


Author(s):  
Raja R. Katta ◽  
Andreas A. Polycarpou ◽  
Jorge V. Hanchi ◽  
Robert M. Crone

Investigation of the slider corner/disk impact process at the Head Disk Interface was carried out using a dynamic elastic-plastic finite element model of a sphere obliquely impacting a thin-film disk. The effect of slider corner radius and impact velocity on critical contact parameters was examined. 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 method to use a physics-based elastic-plastic oblique impact model in conjunction with an analytical normal impact model was proposed to accurately predict coefficient of restitution for a rigid sphere impacting a half-space. This analytical model results compared favorably to the FEA results for the whole range covering low impact angles (primarily normal impacts) to high impact angles (primarily tangential impacts).


2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Raja R. Katta ◽  
Andreas A. Polycarpou ◽  
Jorge V. Hanchi ◽  
Robert M. Crone

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).


Author(s):  
A. van Bael ◽  
P. van Houtte ◽  
E. Aernoudt ◽  
I. Pillinger ◽  
P. Hartley ◽  
...  

2002 ◽  
Vol 69 (5) ◽  
pp. 657-662 ◽  
Author(s):  
L. Kogut ◽  
I. Etsion

An elastic-plastic finite element model for the frictionless contact of a deformable sphere pressed by a rigid flat is presented. The evolution of the elastic-plastic contact with increasing interference is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. The model provides dimensionless expressions for the contact load, contact area, and mean contact pressure, covering a large range of interference values from yielding inception to fully plastic regime of the spherical contact zone. Comparison with previous elastic-plastic models that were based on some arbitrary assumptions is made showing large differences.


1990 ◽  
Vol 112 (3) ◽  
pp. 287-291 ◽  
Author(s):  
F. A. Kolkailah ◽  
A. J. McPhate

In this paper, results from an elastic-plastic finite-element model incorporating the Bodner-Partom model of nonlinear time-dependent material behavior are presented. The parameters in the constitutive model are computed from a leastsquare fit to experimental data obtained from uniaxial stress-strain and creep tests at 650°C. The finite element model of a double-notched specimen is employed to determine the value of the elastic-plastic strain and is compared to experimental data. The constitutive model parameters evaluated in this paper are found to be in good agreement with those obtained by the other investigators. However, the parameters determined by the numerical technique tend to give response that agree with the data better than do graphically determined parameters previously used. The calculated elastic-plastic strain from the model agreed well with the experimental strain.


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