Radiation resistance models for estimating the sound power of thin unbaffled flat plates using the vibration-based sound power method

The Vibration-Based Sound Power (VBSP) measurement method offers distinct advantages over traditional sound-pressure and sound-intensity techniques, particularly in environments with low signal-to-noise ratios or uncontrolled acoustic conditions. This method, based on the elementary radiator model, uses the acoustic radiation resistance matrix along with measured surface velocities to estimate sound power. Previous studies have validated the VBSP approach for various structures, including flat plates, cylindrical and spherical shells, and both simply and arbitrarily curved plates. This work extends the VBSP method to thin unbaffled flat plates by incorporating monopole, dipole, and multipole representations of the radiation resistance. Experimental VBSP measurements on aluminum and steel plates are presented, comparing sound power estimates from each representation and evaluating their agreement with the established ISO 3741 standard. The results demonstrate the high accuracy of the VBSP method in estimating sound power. Key findings show that the sound power of unbaffled plates can be modeled effectively using the equation for two out-of-phase point sources, capturing both monopole and dipole behaviors depending on the acoustic wavelength relative to the plate’s dimensions. This advancement broadens the applicability of the VBSP method to unbaffled structures, offering more precise sound power predictions for a wide range of practical applications. [Work supported by the National Science Foundation.]