NATURAL FREQUENCIES AND STABILITY OF A FLEXIBLE SPINNING DISK-STATIONARY LOAD SYSTEM WITH RIGID-BODY TILTING

The effects of rigid-body tilting on the natural frequencies and stability of the head-disk interface of a flexible spinning disk are studied both by analysis and numerical computation. Another problem of a stationary flexible disk with rigid body tilting subject to a rotating load system is also studied. In the conventional case without rigid-body tilting, these two problems are mathematically identical except for the additional membrane stress terms arising from the centrifugal force. When the rigid-body tilting is included, however, these two problems differ not only by the centrifugal effect, but also by additional terms which arise from the gyrodynamic effect. After properly defining the inner product between two state vectors, the set of equations of motion is proven to fall into the category of gyrosopic systems. Then the derivatives of the eigenvalues of the coupled system are obtained to provide a better understanding of the numerical results.