Analysis of Stresses Induced by Dynamic Load Head-Disk Contacts

Abstract

The dynamic load head-disk contact induced impact stress was studied. A dual channel LDV was used to measure the head-disk relative motion during impact, and an analytical model incorporating the Hertz theory of impact was developed to quantitatively estimate the impact induced contact force and stress based on the LDV-measured results. 70 percent sliders were used in order to compare the results with our previous study. From the estimated maximum contact stresses and the results of our previous study, it was found that when the average maximum stress was 511 MPa, the head-disk interface did not show any damage after 100,000 cycles of repeated head-disk impacts. When the average maximum stress was 880 MPa, however, 100,000 repeated head-disk impacts caused significant wear of the disk’s overcoat even though a single impact did not cause any observable damage. From the analysis it can be seen that a lower head-disk impact velocity and/or a larger radius of curvature at the contacting corner of the slider result in a smaller head-disk impact stress on the disk. Based on the analyses, we estimated the radius of curvature needed for a 50 percent (Nano) slider and a 30 percent (Pico) slider to have at least 100,000 cycles of dynamic load head-disk interface durability. Such radius of curvature can be realized, for example, by edge-blending the sliders. [S0742-4787(00)02901-5]

Transient slider-disk contacts in the presence of spherical contamination particles

“…The numerical results were obtained for typical impact conditions of a slider on a disk, i.e., a slider vertical initial velocity of V y = 0.2 m/s, a disk circumferential velocity of V x = 10 m/s and a coefficient of friction of l = 0.2. These assumed values of the vertical initial velocity and the coefficient of friction correspond to typical cases observed experimentally by, e.g., Fu and Bogy (2000); Liu and Ma (2003); Kato et al (2004). Figure 3 shows the maximum temperature rise as a function of particle radius.…”

Finite Element Simulation of Static Contact of a Slider with Patterned Media

“…Both high flash temperatures and high localized stresses can damage the read/write elements. Several investigations have been conducted in the past to investigate slider/disk contacts (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) . However, few of these investigations have addressed patterned media or planarized patterned media.…”

Shock dynamic characteristics of hard disk drives

“…It is a pity that little literature studies the contributions of it to the HAA dynamic response under impact. However some researchers investigate the effects of the head-disk contact in load/unload process and damage of the disk induced by the head-disk contact stresses [Suk and Gillis (1998); Fu and Bogy (2000), Hua, et a1 (2000)l.…”