Analytical and experimental investigations into active control of sound fields within a 3D enclosure are presented for tonal and bandlimited disturbances. Lead Zirconate Titanate patches mounted on the flexible wall of the enclosure are used as distributed actuators, and polyvinylidene fluoride film mounted on the flexible wall and condenser microphones are used as sensors. The sensors and actuators are used in a digital, adaptive feedforward control scheme to realize `local' noise and vibration control. For tonal disturbances, the developed analytical model is found to yield results that are in good agreement with the experimental observations. Different cases of bandlimited disturbances are considered in the experiments. These cases include multiple panel and/or enclosure resonances. For bandlimited disturbances, the control scheme is found to be effective in identifying the dominant resonances and realizing significant noise reductions at the dominant modes. However, the local noise reductions realized for bandlimited disturbances are not as high as those realized for tonal disturbances. Issues such as performance functions are also explored in the investigations.

Date Published: 16 April 1998
PDF: 12 pages
Proc. SPIE 3321, 1996 Symposium on Smart Materials, Structures, and MEMS, (16 April 1998); doi: 10.1117/12.305572

Published in SPIE Proceedings Vol. 3321:
1996 Symposium on Smart Materials, Structures, and MEMS
Vasu K. Aatre; Vijay K. Varadan; Vasundara V. Varadan, Editor(s)