Natural Frequencies Of A Thin Disk, Clamped By Thick Collars With Friction At The Contacting Surfaces, Spinning At High Rotation Speed

Abstract Prediction of the natural frequencies of a rotating disk requires accurate representation of the disk membrane stresses caused by rotation. These stresses depend strongly on the membrane stress boundary condition at the clamping collar. This research evaluates experimentally the validity of the standard models of this boundary condition: vanishing radial stress, vanishing radial displacement, or finite stress at the center of an integral disk and collar assembly. It shows that they can lead to over 13% error in prediction of the natural frequencies of the disk spinning at high rotation speed. The error occurs because the idealized models do not include friction and stiction at the disk/collar interface and slippage of the disk between the collars. Stiction and slippage also cause hysteresis of the disk natural frequencies with start/stop cycles of rotation speed. Inclusion of an empirically determined friction traction at the collar diameter reduces the error in predicted frequencies to less than 1%.