Electro-elastic Analysis And Active Vibration Control Of Piezoelectric Laminated Plates And Shells

The vibration control of flexible structures is a very important problem in the field of aviation and spaceflight. This is due to the characteristics of large scale, low stiffness and flexibility of the space structures which need a working environment to fit the demands of high precision instruments in it . Because this kind structures is a distributed parameter system, the classical point sensors and actuators can not realize this purpose efficiently (if some sensor or actuator is just located on a node of some modal if will be not in action). The recent presence of piezoelectric film (PVDF, PZT) promotes the development of distributed vibration control method. This method needs two pathes of piezoelectric films sticked on the top and bottom of the flexible structure being the sensor and actuator respectively. Using this method to realize vibration control of space flexible structures is becoming an attractive research field recently due to its important values in theory and engineering. Based on a lot of relating literature, systematic studies on the subject have been performed and following results have been achieved by the author.1. Based on the equation of piezoelectricity and Hamilton principle, a generalized piezoelectric laminated thin shell is analysed and the dynamic equation is derived.2. The generalized conforming plate element is extensivly used in structure analysis for its good performance. This element is adopted in this research. A new piezoelectric laminated plate element is erected by the author. Having only one degree of electrical freedom in each piezoelectric layer, this element has implicit concept and can be used for the case of multiple piezoelectric layers existed in the laminated plate. Whereas the works of some researchers are limited in the case of only one piezoelectric layer. In his paper, the Bailey beam, Crawley plate and piezoelectric PVDF bimorph beam are analysed using the program worked out by the author and the comparison of these results with that of experiments shows that the concidence of these results very well, which verified the high precision of the piezoelectric plate element erected by the author.3. Based on Hamilton principle, the equation of active vibration control of the piezoelectric laminated plate is derived. In this study the item of the potential energy is derived from the analysis of electro-elastic coupling, but not as in some references only the elastic potential energy is considered. In Hwang's piezoelectric plate element, the effect of electricity is transformed to a equivalent extra force, which is not rigorous enough in theory. This defect is overcome in this paper.4. Using the derived active control equation, the optimal placement of actuator patches is studied. Because each patch of piezoelectric film is sticked separately on the surface of structures and there are very small seams among them to insulate each other, the sensor output of electrical charge will be cancelled in one patch which covers the area of positive and negative strains in the sametime. This phenomenon will reduce the efficiency of distributed sensing and actuation. Six...