Controlled Reverberant Acoustic Excitation Capabilities at NASA Langley Research Center

Abstract

Launch vehicles are exposed to intense levels of acoustic noise. Simulation of these acoustic loads at room temperature is performed in the reverberation chamber of the Structural Acoustics Loads and Transmission (SALT) facility at NASA Langley Research Center. The ability to control the level and shape of reverberant acoustic excitation spectra is demonstrated for space vehicle launch spectra, uniform power density one-third octave band excitation (pink noise) and excitation characterized by serrated pink noise spectra. A maximum 141 dB Overall Sound Pressure Level (OASPL) was achieved for a simulated launch spectrum covering the 40-2000 Hz one-third octave frequency bands and for a flat pink noise spectrum extending over a 40-1250 Hz frequency range. The acoustic test facility, the test equipment and instrumentation, and the control and data acquisition systems used in the measurements are described in detail. The results show high accuracy (within 1 dB of each defined one-third octave band level) and repeatability in the simulation and control of the reverberant acoustic excitation spectra.