Study Of The Dynamic Characteristics Of Laminated/Functionally Graded Piezoelectric Plates

Piezoelectric composites are widely used in underwater acoustic, electro-acoustic and ultrasound and other fields because of their various advantages like, fast response, small acoustic impedance, high electromechanical coupling coefficient, flexible, and easy processing, etc. Piezoelectric composites can be applied to fabricate periodic structures with the aim to attenuate the structural vibration. The main works include four parts as following:First, using the Bloch theorem and the plate theory, the dynamic equilibrium equation, boundary conditions and periodic boundary conditions are deduced based on the elasto-dynamics mechanics. The eigenvalue equation is solved by using the differential quadrature element method (DQEM), from which the dispersion curves are obtained. And by comparing with other literatures, the correctness of differential quadrature element method (DQEM) is proved.Second, laminated plate with periodic piezoelectric patches on the top and bottom surfaces is considered. Dispersion characteristics of the laminate plate for in-plane and out-of-plane waves are investigated. The influences of the stacking sequence on the width of attenuation zone are studied. With the stacking sequence changes of the laminated plate, the width of attenuation zone is varying. Both the symmetrically cross-by and anti-symmetrically cross-by are considered. Dynamic response of the laminated plate with finite-size periodic piezoelectric patches is analyzed by using the finite element software ANSYS. Harmonic analysis results verify the correctness of attenuation zone diagram by the differential quadrature element method (DQEM). Transient simulation results show that the amplitude of vibration of the periodic laminated plate is effectively weakened when frequency falls within the attenuation zone range.Third, the attenuation zones of the periodic laminated plate by using the gain control algorithm are analyzed. The attenuation zones of the periodic laminated plate are affected by the feedback gain G.Fourth, functionally graded plate with periodic piezoelectric patches on the top and bottom surfaces is considered. Dispersion characteristics of the laminate plate for in-plane and out-of-plane waves are investigated. The different functionally graded materials and volume fraction of the ceramic index have significant impacts on the width of attenuation zone.