Vibration analysis of a spinning disk using image derotated holographic interferometry

The application of image derotated holographic interferometry to study the resonant response of a rotating steel disk at speeds up to 8000 RPM is discussed. The rotational motion of the disk is optically removed by passing the image of the rotating disk through a prism that is traveling at half the rotational speed of the disk. Off-axis double-pulsed laser holography is then used to record the disk resonant vibratory response. The first five diametrical modes and one complex mode of disk vibration are obtained at various RPM. The effects of disk imbalance, misalignment of optical and mechanical axes of rotation and system-excited modes of vibration are also addressed. Selected experimental results are compared to those obtained using finite element analysis.