The dynamics of a flexible disk rotating near a rigid flat plate are characterized experimentally using a laser Doppler vibrometer. The goal of the investigation was to determine the mechanism by which the gap between the disk and the base plate varies with time. A periodic averaging scheme is used to separate the instantaneous gap signal into a periodic component phased to the rotational position of the disk and an independent random component. The periodic component is shown to dominate, demonstrating that the gap variation is caused by permanent deformations of the disk moving past a fixed point. The base plate stabilizes the disk by flattening the deformations, and the gap variations can be further reduced by increasing disk rotational speed. Disks having 100 and 180 Am thickness were investigated; the thicker disks are shown to have less residual curl. The stabilizing influence of the base plate is lost as the hub height is increased, which implies that hydrodynamic forces are essential to the stabilization mechanism. The mean disk shape is generally a linear function of radius; no self-regulating region was observed.
R. w. Wlezien,
D. K. Miu,
"Characterization Of Rotating Flexible Disks Using A Laser Doppler Vibrometer," Optical Engineering 23(4), 234436 (1 August 1984). https://doi.org/10.1117/12.7973314