Smart foam is an active/passive hybrid noise control approach, which consists of a passive acoustic matrix with embedded active elements. Smart foam elements with embedded electro-magnetic actuators were designed for optimum performance for tonal noise control in the frequency range of 80 - 300 Hz. Lightweight smart foam actuators with piezoelectric PVDF element were designed for active broadband noise control. Laboratory experiments were conducted on a stiffened composite panel to evaluate active tonal and broadband noise reduction with smart foam treatment. A multi-input, multi-output (MIMO), filtered-X, feed-forward controller was used to implement active control using smart foam actuators by minimizing the error signals from an array of error microphones. Both structure-borne and airborne excitations were used. For tonal noise control, the structure was excited with multiple harmonics in the frequency range of 80 - 300 Hz, whereas a filtered white noise from 300 - 800 Hz was used for broadband noise control tests. The radiated sound field was measured with an array of microphones in the anechoic chamber. For active tonal control, reductions of 17, 12 and 4 dB at 105, 210 and 315 Hz were achieved. Active broadband noise control using smart foam elements reduced the error microphone outputs by 3.5 dB.
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