Extending the vibration-based sound power method to determine the sound power radiated from acoustic sources

A vibration-based sound power (VBSP) method has been developed as an alternative method for determining the acoustic energy radiated from structures. Many acoustic sources, such as a blender or motor, have sound power contributions that originate from within the structure and therefore cannot be scanned properly using a vibrometer. For these types of sources, a rectangular enclosure with five rigid sides and a single mylar side was fabricated to enclose the acoustic source, so that the VBSP method could be utilized to obtain the radiated sound power. A calibration curve was developed to account for the enclosure effects on these sources, and this curve is used to adjust the measured results to give the true free-field radiated sound power. Experimental results will be shown comparing the sound power obtained from the adapted VBSP method with the sound power of the source obtained in a reverberation chamber using the ISO 3741 standard. Furthermore, computational results will be shown comparing the sound power obtained through the boundary element method (BEM) with the sound power obtained by using the velocities calculated from that model processed with our VBSP method. Funding for this work was provided by the National Science Foundation (NSF).