Active Structural Acoustic Control of Sound Transmission Into a Laminated Composite Enclosure Using Piezoelectric Actuator-Sensor Pair With a Frequency Weighted Optimal H₂ Controller

The use of laminated composite materials in aircraft or automobile structures, though very common due to various advantages of these materials, often escalates the overall noise and vibration level. An active structural acoustic control (ASAC) strategy based on a frequency weighted optimal H₂ controller is developed in the present work to attenuate the transmitted sound into an enclosure surrounded by laminated composite panels. A state-space model based on a two-way coupled fluid-structure interaction analysis using Green’s theorem is proposed to include the influence of the flexible panels on the enclosed fluid (air) and vice-versa. Few points within the cavity are identified as the observer locations based on the maximum sound pressure level (SPL) within the enclosure due to external mechanical excitation. The SPL averaged over these locations is used as the performance vector for the proposed H₂ controller. A feedback control strategy is then developed using surface bonded collocated IDE-PFC actuators and PVDF sensors while optimizing the quadratic H₂ norm between the external excitation and the performance vector with a limit on the actuation voltage. Numerical simulation shows a maximum of 11.4 dB of averaged SPL reduction achieved inside the enclosure for a particular configuration.