On the noise transmission and control for a cylindrical chamber core composite structure

The vibroacoustic properties, sound transmission behavior, and noise transmission control of a novel chamber core composite cylinder are studied. An approximate uniform shell model of the sandwich cylindrical chamber core structure is developed to aid in the calculation of the ring frequency and external critical frequency. Acoustic modal parameters are analytically and experimentally obtained. The structural modal parameters are identified from measured data. The coupling between structural and acoustic modes is investigated. The sound transmission into the cylindrical chamber core is experimentally characterized, where the stiffness-, cavity resonance-, mass-, and coincidence-controlled zones are identified. Finally, the addition of fills to the wall chambers of the chamber core is investigated as a part of passive control study, which also serves to corroborate the model development.