Robert L. Clark, Jr.
Dept. of Mech. Eng. and Mater. Sci., Duke Univ., Durham, NC 27706
Chris R. Fuller
Virginia Polytech. Inst. and State Univ., Blacksburg, VA 24061
An aluminum cylinder, measuring 1.22 m long with a wall thickness of 2.77 mm and a diameter of 0.254 m, was configured with two rigid end caps and instrumented with piezoceramic actuators and polyvinylidene fluoride (PVDF) sensors for narrow-band active structural acoustic control. All tests were performed in an anechoic environment. In the first test case, the cylinder was driven with a shaker on one end cap, exciting the ``accordion mode'' of the structure. Significant levels of sound radiation (90 dB) from the end caps were observed in this mode of vibration and the piezoceramic actuators were more than sufficient for controlling the structural acoustic response, yielding 35 dB of global attenuation. In the second test case, the cylinder was driven radially to excite the (0,1) mode of the cylinder as well as higher-order modes to demonstrate the capability of the piezoceramic actuators for controlling the structural acoustic response of the ``breathing mode'' as well as higher-order cylinder modes. Results from this preliminary study suggest that piezoceramic actuators and PVDF sensors are viable transducers for creating an adaptive/sensory structure for active structural acoustic control on cylinders. [Work supported by ONR.]