Analysis of flat and curved piezo-actuators for vibration control of cylindrical shells
Abstract
Analytical investigations on flat and curved piezo-actuators are performed in order to design actuator parameters for coupling to lower order cylindrical shell modes. Equivalent forces exerted by different shaped piezo-actuators are studied. It is shown that out-of-phase driven bi-morph piezo-actuators exert line moments along their boundaries regardless of shape. Their wavenumber transforms are presented in order to give a better understanding of the mode coupling characteristics of these piezo-actuators when surface-bonded to structures. It is shown that the out-of-phase configuration couples strongly to higher order modes due to the line moments. Curved bi-morph piezo-actuator models are developed to understand the influence of curvature. The models are developed using static assumptions. Two drive configurations are studied: in-phase and out-of-phase. The in-phase model exerts line forces and uniform pressure load over the patch area. The out-of-phase model exerts line moments. The static assumptions of the curved model are verified using a wave propagation approach. The model developed does reasonably well for actuator thicknesses up to a quarter thickness of the shell at resonances and up to half the shell thickness at off-resonances. Beyond this thickness the dynamic effects of the actuator mass and stiffness cause deviations. Finally, the developed model is used to propose design guidelines using properties like size, location, thickness of the actuator to excite lower order modes in a cylindrical shell. It is shown that in-phase actuation is better for exciting lower order shell modes than out-of-phase actuation. Also, the shell aspect ratio, the actuator size and location are important parameters influencing the shell response. In order to excite lower order cylindrical shell modes and alleviate the spillover problem, large actuators will be required.
Degree
Ph.D.
Advisors
Jones, Purdue University.
Subject Area
Engineering|Mechanical engineering|Mechanics
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