Designing, Modeling, And Applications Of Piezoelectric Composite For Underwater Vibration Control

The vibration is a fatal problem for an air craft or a submarine. Active control of the vibration with smart structures has been investigated by an increasing number of researchers in recent years. The vibration can be actively altered or decreased by the smart structure in which the sensor senses vibration of the structure, and then the actuator acts accurately under the control of micro-electronics system. Piezoelectric composite materials, the important part of smart structures, have the ability to perform both sensing and actuating functions.The 1-3 piezoelectric composites consist of piezoelectric rods parallel embedded across the polymer. Such materials have been exploited effectively in the pulse-echo transducers used in medical ultrasonic imaging with its high coupling factor and low acoustic impedance. And it has become a viable candidate for smart actuation in underwater vibration controlling. In this paper, a simple model of 1-3 piezoelectric composite is advanced for the material properties where both the oblique angles and the volume fraction of the piezoelectric ceramic rods are calculated to maximize the electromechanical coupling factor, the acoustic impedance, and the hydrophone figure of merit. The results indicate that the electromechanical coupling factor is highest at the 87% of the fraction of the ceramics and at 28° when the piezoelectric rods are inclined, and the acoustic impedance linearly increases with the faction of the ceramics, and the hydrophone figure of merit is maximal at 12% of the fraction of the ceramics. The selection of the piezoelectric ceramics and the polymer is also discussed in detail. It indicates that the ceramics have a greatly effect on the coupling factor and hydrophone figure of merit. Therefore, the modeling is a good way to design the piezoelectric composite in the smart structure for vibration control.