The transient vibration due to imbalance of a lightweight rotor that comprises flexible blades, disk, shaft, and rigid bearings is analyzed by a finite element method. The dimensions of matrices used in the computation are reduced by representing the shaft and blades by beam elements, and the disk by annular elements. The computed results are compared with the experimental data obtained by a test conducted on a small model rotor with a blade loss simulator. A fairly good agreement was obtained between the computed and experimental results.
