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107 - Piezoelectrically induced vibrations of sandwich panels with interlayer slip
Heuer R.
Abstract
Considering vibration control of flexible structures, the corresponding distributed actuators are frequently realized by embedding layers of piezoelectric materials. Such devices are often constructed in form of thin panels, plates or shells. Activation renders piezoelectrically induced strains that are imposed to generate the distributed input of the control system. The present paper is concerned in detail with actuating piezoelectric effects in sandwich panels, where special emphasis is given to the identification of the piezoelectric actuation as a source of selfstress. It is demonstrated that piezoelectrically induced strains conveniently, within a multiple field approach, can be interpreted as eigenstrains acting in a background panel without piezoelectric actuators. The identification of piezoelectrically induced strains as eigenstrains, likewise to thermal strains, indeed may be viewed as the key for the understanding of piezoelectric actuation. It has been stated already in the literature that the analogy between the piezoelectric effect and the thermal and hygrothermal effect is important because it enables the analyst and designer to transfer all available thermoelastic and hygrothermal solutions to solve problems involving piezoelectric materials. This analogy is utilized in the present paper, where the layer-wise theory is applied to flexural vibrations of panels composed of three symmetrically arranged layers made of dissimilar isotropic materials. Contrary to the classical theory of perfectly bonded laminates, the following study concentrates on panels where the inter-laminar connections exhibit a viscoelastic interlayer slip between the outer faces and core. The influence of transient piezoelectric actuation is characterized by effective terms of the imposed mean strain and curvature. The corresponding sixth-order initial-boundary value problem of the flexural vibrations is formulated. In a numerical study, frequency response functions for the deflection of sandwich panels due to imposed time-harmonic thermo-piezoelectric eigenstrains are determined, which represent important input functions for computational methods in the frequency domain.
Citation
Heuer R.: Piezoelectrically induced vibrations of sandwich panels with interlayer slip, CD-ROM Proceedings of the Thirtheenth International Congress on Sound and Vibration (ICSV13), July 2-6, 2006, Vienna, Austria, Eds.: Eberhardsteiner, J.; Mang, H.A.; Waubke, H., Publisher: Vienna University of Technology, Austria, ISBN: 3-9501554-5-7