Lalande, Frederic2014-03-142014-03-141995-04-05etd-02132009-171909http://hdl.handle.net/10919/37352When discrete piezoelectric actuator patches bonded on structures are used for active shape, vibration, and acoustic control, the desired deformation field in the structure is obtained through the application of localized line forces and moments generated by expanding or contracting bonded piezoelectric actuators. An impedance-based model to predict the dynamic response of cylindrical shells subjected to excitation from surface-bonded induced strain actuators is presented. The essence of the impedance approach is to include the actuator/structure impedance ratio in the calculations of the actuator forces applied to the structure, which will retain the dynamic characteristics of the actuators. The appropriate representation of the loading due to in-phase and out-of-phase actuation is discussed. Due to the curvature of the shell, the representation of the in-phase actuation with an equivalent in-plane line force applied along the edge of the actuator results in the application of erroneous rigid-body transverse force. To avoid these rigid body forces, the action of the actuator needs to be represented by am equivalent in-plane force and a transverse distributed pressure applied in the region of the actuator patch to maintain the structure self-equilibrium. A full derivation of the impedance model is included, taking great care in the structural and actuator impedance definition. It is found that the actuator's output dynamic force in the axial and tangential direction are not equal. Various case studies of a cylindrical thin shell are performed to illustrate the capabilities of the developed impedance model. The in-phase and out-of-phase actuation authority of induced strain actuators bonded to the surface of a shell is compared. It is shown that out-of-phase actuation has better authority in exciting the lower order bending modes, while in-phase actuation has better authority in exciting the higher order circumferential modes. Dynamic finite clement analysis has been performed using piezoelectric elements available in ANSYS 5.0. The good correlation between the finite clement results and the impedance model confirms the analytical solution. Experimental data of a circular ring actuated in-phase and out-of-phase by a piazoelectric material (PZT) were also compared to the derived impedance model.xviii, 152 leavesBTDapplication/pdfenIn Copyrightstresses - structuralLD5655.V856 1995.L358Dissertationhttp://scholar.lib.vt.edu/theses/available/etd-02132009-171909/