Analytic study on 1:1:1 internal resonance nonlinear dynamics of a liquid-filled spacecraft with elastic appendages

The coupling dynamics of the pitching of spacecraft, thesloshing of liquid fuel and the vibration of elastic appendages areinvestigated. The coupling dynamics equations deduced by using H-O principleare adopted. The attitude of spacecraft is controlled. The multiple scalemethod is proposed to analyze the 1:1:1 internal resonance of therigid-liquid-elastic coupling system. The effect mechanism of the couplingdynamics are obtained by the analytic study. The amplitude-frequencyresponse switches between soft and hard spring type with liquid depth. Theresonances of the spacecraft and elastic appendages occur at both of thenatural frequencies of spacecraft and elastic appendages.