Modeling of Piezoelectric Smart Structures Including Absorbing Materials for Cabin Noise Problems

초록

Piezoelectric smart structures are widely recognized as promising technology for cabin noise problems. However, because of the finite number of piezoelectric actuators and sensors the structure can handle limited modes so that its effectiveness is restricted to low frequencies. On the other hand, passive approach in cabin noise which uses sound absorbing materials, can reduce the transmitted noise at high frequencies. Thus, to suppress the transmitted noise in the cabin in a wide frequency band, we propose to put passive sound absorbing material on the piezoelectric smart structure. The active piezoelectric smart structure will function at low frequency while the passive sound absorbing material work at high frequency for transmitted noise reduction. To prove its effectiveness, a numerical study is performed. It includes the finite element modeling of piezoelectric smart structures with sound absorbing material. Sound absorbing materials can be represented as impedance surface and it turns out to be damping matrix in finite element formulation. The sound interaction between the structure and the acoustic cavity also is taken into account. Sound transmission at a wide band is evaluated numerically. The validity of the results will be proven by an experimental comparison. By constructing the numerical model of the smart structures including sound absorbing materials a true design of the structures that function in a wide band can be obtained.