A new class of smart foams is introduced to simultaneously control the vibration and noise radiation from flexible plates coupled with acoustic cavities. The proposed smart foam consists of passive foam/piezoelectric composite layers. The proposed smart foam can simultaneously control structural and acoustic cavity modes over a broad frequency range. A comprehensive theoretical study of the smart foam elements is introduced, in order to optimize the design and performance of this hybrid actuator. A finite element model is developed to study the interactions among the smart foam...