Vibration and critical speeds of a spinning annular disk of varying thickness

The equation of motion of a spinning isotropic annular plate of linearly and exponentially varying thickness is formulated based on the Lagrangian approach and the assumed mode method. The plate is assumed to be elastic in the spinning motion and the initial stress fields in the plate are derived assuming the plane stress condition. The natural frequencies and critical speeds for vibration modes consisting of radial nodal lines without any nodal circle are presented for simply supported-simply supported and clamped-free edge conditions.