Vibration of a Shaft Passing through a Critical Speed : 1st Report Experiments and Numerical Solutions

Abstract

The vibrational problem which occurs during passage through a critical speed has been investigated with regard to the maximum deflection of shaft. In this paper, we shall study the vibrational characteristics, such as the deflection of a shaft, the angular velocity of whirling motion and the phase angle between the unbalance and the whirling motion, under a uniform angular acceleration over the wide range of angular velocity of a shaft. From the numerical solutions and the experiments on a simple system with one disk, it is clarified that the amplitude of the whirling motion causes a beat after running through the critical speed and in case of acceleration the maximum (minimum) amplitude of beat occurs when the angular velocity of the whirling motion becomes maximum (minimum) and that the phase angle becomes nπ+π/2 radians when the angular velocity of whirling is equal to the angular frequency corresponding to the critical speed of the system.