ORDER FROM DISORDER: A CASE STUDY OF THE EFFECTS OF STRUCTURAL INHOMOGENEITY ON STRUCTURAL-ACOUSTIC INTERACTION.

摘要

The method of Statistical Energy Analysis (SEA) is commonly used to estimate the response of structures to acoustic excitation. In many cases, the SEA analysis is limited to determination of the mean-square response averaged over both the spatial extent of the structure and bands of frequency. However, when SEA is used to support the design of practical hardware, one needs to be aware of the variability about this mean estimate in order to determine a reasonable maximum or upper bound of the response. In this work, the variability of a non-homogeneous lightweight aerospace (satellite equipment panel) structure's response is investigated using theoretical and empirical techniques. The structure's spatial and ensemble vibration response variabilities are evaluated using in-situ measurements. The structure’s input power variability (structural-acoustic coupling) is evaluated computationally from the structure's radiation efficiency. The results show a trend at the mid to low frequencies: as the inhomogeneity of the complex structure is increased, the variability (in a band-average sense) of the structural-acoustic coupling is decreased. Future work is required to develop semi-empirical methods for estimating the variability associated with an SEA prediction of this type of system.