Transmission of Sound and Vibration to a Shroud-Enclosed Spacecraft

Abstract

The flow of high-frequency vibratory energy to a shroud-enclosed spacecraft is discussed. Two paths of energy flow are considered: first, the acoustical path along which energy flows from the external exciting field through the shroud and interior acoustic space to the spacecraft; and, second, the mechanical path along which energy flows from the external field through the shroud and spacecraft mounting trusses to the spacecraft. Theoretically predicted response levels in octave frequency bands for a model of the OGO spacecraft assembly are presented. These predictions show that the spacecraft response to energy transmitted along the acoustic path is at least a factor of 10 greater than the response due to energy transmitted along the mechanical path over the frequency range 250–8000 Hz. Methods to reduce the spacecraft response are discussed. [Research supported by National Aeronautics and Space Administration.]