Passive control of sound transmission through a double panel using heterogeneous (HG) blankets, Part III: HG design strategies

摘要

This is the third of three companion papers concerned with the modeling and optimization ofheterogeneous (HG) blankets, which are used in this investigation to reduce the soundtransmission through double panel systems. HG blankets consist of poro-elastic media with smallembedded masses, which act similar to a distributed mass-spring-damper-system. Previous workhas shown that proper tuning of the HG blankets can result in noise and vibration reduction atlow frequencies without compromising the inherent high frequency performance of the poroelasticmedia. The masses can be tuned to certain frequencies by varying their weight, shape, andposition within the poro-elastic media. In this paper a theoretical and experimental comparison ofdifferent design techniques for choosing the location and tuning of embedded masses ispresented. These design techniques are the random placement of the mass inclusions, the massplacement using a modal design and an optimized design technique using a numerical designtool. Future work includes expanding the model and experiment to multiple panel systems, andinvestigating the effect of distributed masses on HG performance.