Qualification of Spacecraft Equipment: Early Prediction of Vibroacoustic Environment

摘要

This paper proposes a new, flexible, and accurate method for predicting the vibroacoustic environment, which is andriving load case in the development of panel-mounted spacecraft units. This method accounts for the physicalnparameters that intervene in the dynamically coupled response of units and panels to the impingement of the soundnradiated by the rocket engines. Accordingly, it can simplify the costly overdevelopment imposed by testing standardsnrelying on simple mass formulas and significant safety factors. It quickly provides acceleration and force levels fornvibration tests, can be applied during any project phase, and allows for the coupling of models with different levels ofnmaturity, while still avoiding the lengthy processing imposed by finite and boundary element tools. It uses impedancemobility for dynamically condensing panels and units in a compact and modular way. The acoustic load experiencednby a panel is characterized by means of physical reasoning based on acoustic diffraction and joint acceptancenbetween the mode shapes and diffuse field. Predicted levels are presented for an actual spacecraft panel coupled withnseveral units, and are compared to detailed vibroacoustic analysis using finite and boundary element methods, testnresults, and ESA and NASA standards.