High Velocity Oblique Impact and Coefficient of Restitution for Head Disk Interface Operational Shock

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).

[1]  Analytical and Experimental Elastic-Plastic Impact Analysis of a Magnetic Storage Head-Disk Interface , 2009 .

[2]  Mike Suk,et al.  Effect of Slider Burnish on Disk Damage During Dynamic Load/Unload , 1998 .

[3]  C. Thornton.  Coefficient of Restitution for Collinear Collisions of Elastic-Perfectly Plastic Spheres , 1997 .

[4]  Kyriakos Komvopoulos,et al.  Three-Dimensional Contact Analysis of Elastic-Plastic Layered Media With Fractal Surface Topographies , 2001 .

[5]  K. Johnson.  Contact Mechanics: Frontmatter , 1985 .

[6]  W. Goldsmith,et al.  Impact: the theory and physical behaviour of colliding solids. , 1960 .

[7]  Frank E. Talke,et al.  The transition between sliding and flying of a magnetic recording slider , 1987 .

[8]  G. Hamilton,et al.  Explicit Equations for the Stresses beneath a Sliding Spherical Contact , 1983 .

[10]  Colin Thornton,et al.  Coefficients of restitution for elastoplastic oblique impacts , 2003 .

[11]  F. C. Lea.  Hardness of metals , 1936 .

[12]  Bo Liu,et al.  Visualization and characterization of slider-disk interactions in dynamic load/unload processes , 2003 .

[13]  Andreas A. Polycarpou,et al.  Elastic contact mechanics-based contact and flash temperature analysis of impact-induced head disk interface damage , 2007 .

[14]  Masahiro Kawaguchi,et al.  Friction and durability characteristics of ultrathin perfluoropolyether lubricant film composed of bonded and mobile molecular layers on diamond-like carbon surfaces , 2004 .

[15]  George G. Adams,et al.  The Coefficient of Restitution for a Planar Two-Body Eccentric Impact , 1993 .

[16]  S. C. Hunter.  Energy absorbed by elastic waves during impact , 1957 .

[17]  L. Vu-Quoc,et al.  Modeling the dependence of the coefficient of restitution on the impact velocity in elasto-plastic collisions , 2002 .

[18]  Wen-Ruey Chang,et al.  Normal Impact Model of Rough Surfaces , 1992 .

[19]  Magnetic erasures due to impact induced interfacial heating and magnetostriction , 2000 .