Bertrand J. Brevart
Chris R. Fuller
Vib. and Acoust. Labs., Dept. of Mech. Eng., Virginia Polytech. Inst. and State Univ., Blacksburg, VA 24061-0238
Experimental results of studies on active vibration control in fluid-filled piping systems are presented. Reductions of the total power flow, i.e., the power flow in the shell wall and the power flow in the fluid field, have been achieved by means of external radial forces applied to the structure. Axisymmetric wave propagation was first considered, using PVDF cables both as actuators and sensors. The shell radial displacement beyond the control discontinuity was reduced by 7 to 20 dB in a large frequency range. In addition, the internal pressure field was globally attenuated by the external forces. Considering a point force disturbance at low frequencies, attenuations of the shell motion associated with higher-order modes (n=1,2) have been achieved, by means of shaped PVDF films as error sensors and point forces as structural control inputs. [Work supported by ONR.]