Modal Analysis of Transverse Vibration of a Spinning Rocket Based on Timoshenko Beam

The spinning rocket is simply modeled as a Timoshenko rotor. The natural modal of transverse vibration of spinning rocket in free flight is studied based on finite element method. Under consideration of gyro-effect and shear effect, finite element equation and frequency equation of transverse vibration of the spinning rocket are both presented based on Timoshenko beam model and theory of rotor dynamics. With the aid of presented frequency equation, modal analysis of a certain rocket could be made by adopting Rayleigh beam and Timoshenko beam model separately. Further, precession frequencies of transverse vibration of the rocket for different beam models have been contrasted and the discussion about the effects of rotate speed and slenderness ratio of the rocket on the inherent characteristics has been done.