An Experimental Study of the Parameters That Determine Slider-Disk Contacts During Dynamic Load-Unload

Abstract

The parameters that appear to determine if slider-disk contact occurs during dynamic loading are the relative loading velocity at the instant of load and the initial pitch and roll of the slider at its unloaded state. A dual-beam LDV system is employed in this study to measure the displacement, pitch, and roll during dynamic loading for five different standard 3380-type sliders in order to investigate the effects of the initial pitch and roll. The effects of the initial height and control loading speed are also examined by using the dual-beam LDV and acoustic emission (AE). Based on the experimental results, we propose several slider-disk contact criteria. Among them, the criterion based on the initial diagonal slope and the peak loading velocity gives a simple way to predict if slider-disk contacts will occur, but it overlooks the effect of the signs of the initial pitch and roll. A three-dimensional criterion based on the peak velocity and the initial pitch and roll angles appears to be more reliable. Using either criterion, it is found that high peak loading velocity causes slider-disk contact, and sliders with larger initial pitch or roll angles are more likely to hit the disk.