Sound Vibration Analysis at the Time of an Artificial Satellite Launch

Abstract

In spacecraft system acoustic tests, one often sees local pressure increase in the narrow gap between spacecraft primal structures and components facing toward the fairing wall. This acoustical environment load to the components differs from that the components are tested alone and the flight acoustic environment may not be actually simulated in the ground testing. In this paper, in order to clarify the mechanism and evaluate this pressure increase, basic experiment including acoustic testing and vibration modal survey are employed. It is found that the main reason of the phenomenon is dominated by the acoustic cavity on the appropriate boundary condition rather than structure vibration. Boundary element method is used to analize the phenomenon and comparison of analysis and experiment results are carried out. The analytical and experimental results agree well. Furthermore, it is understood that the phenomenon of local sound pressure level increase is dominated by the acoustical standing wave mode (1, 1) which can be predicted by the presented methods.