Analytical predictions for diffuse field sound transmission loss are compared with measurementscollected in NASA Langley’s Structural Acoustic Loads and Transmission facility. Thefacility consists of a reverberant source room coupled to an anechoic chamber through a window.During a transmission loss measurement, test articles are situated in the window, thesource room is ensonified, and the sound power through the structure is measured using anarray of intensity probes on the anechoic receiving side. Typically, the sound field in thesource room of a transmission loss suite is assumed to be diffuse, which implies that theintensity incident on the test article is equally probable from all angles of incidence. However,it is common to neglect the contribution of sound waves near grazing incidence whenpredicting transmission loss. While there may not be a strong physical justification, this simplecorrection generally leads to better agreement between predictions and measurements.An alternative correction can also be used that accounts for the finite dimensions of the testpanel. The purpose of this study is to assess the accuracy of several analytical transmissionloss models that include these types of corrections. Specifically, predictions are comparedwith measurements acquired on simple structures including different sized limp panels andunstiffened metallic plates.
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