Analytical Prediction and Test Correlation of Spacecraft Cavity Acoustic Environment

Abstract

Spacecraft design often includes internal cavities or compartments that house critical components and/or payloads. In fact, spacecraft missions that carry cargo within special compartments became more prevalent in recent years. The acoustic environment within a cavity directly translates to a random vibration environment and the resulting structural loads might be excessive for sensitive payloads to endure. Hence, the analysis to accurately estimate the cavity environment is often considered one of the critical design processes in spacecraft development. The work presented by the authors in the 2014 AIAA SciTech conference demonstrated that Statistical Energy Analysis (SEA) and Boundary Element Method (BEM) can be used in predicting the cavity environment with reasonable correlation to the test data. However, it did not address the spatial variation of acoustic environment within the cavity that was evident in the BEM analysis results. This paper discusses the outcome of subsequent acoustic tests, as well as the analytical model correlation effort to improve cavity acoustic environment prediction. The spacecraft acoustic test was performed using additional instrumentations to better document the acoustic pressure gradient within the cavity. Several enhancements and fidelity improvements were applied to the analytical models, including the use of fully detailed spacecraft model for BEM analysis. The current study focuses on the low frequency correlation using BEM, as well as comparison between SEA result and averaged test data for high frequency correlation.