The Residual Shaft Bow Effect on Dynamic Response of a Simply Supported Rotor With Disk Skew and Mass Unbalances

The effect of residual shaft bow on the dynamic response of a simply supported single disk rotor with disk skew and mass unbalances is studied. The influence of disk-positioning between bearings also is investigated. Under the combined influences, the zero amplitude speed for a thin disk and the first zero amplitude speed for a thick disk are shown to be smaller than or equal to the square root of the ratio of residual bow amplitude to unbalance eccentricity. Moreover, when the rotor passes through the critical speed associated with disk pitch, the rotational amplitudes are greater than when it passes through the first translational critical mode. The results, shown in this study, can significantly assist in the determination of rotor unbalances.