Vibration characteristics of FG saturated porous annular plates integrated by piezoelectric patches on visco-Pasternak foundation

The vibrational behavior of a three-layered annular plate is considered in the present study. The plate is composed of a functionally graded (FG) porous core which is saturated by fluid and two piezoelectric patches that are bonded to the core and are subjected to the electric field. The whole of the structure is also rested on visco-Pasternak elastic foundation. The material properties of the FG porous core vary through the thickness direction based on different patterns which are called porosity distributions. Love-Kirchhoff's hypothesis and Hamilton's principle is employed to extract the governing motion equations and boundary conditions and following it, they are solved by generalized differential quadrature method (GDQM) for various boundary conditions. After ensuring the validity of the results by comparing them with known data in the literature, the effect of the most important parameters on the results is considered. It is seen that the effect of the porosity coefficient on the natural frequencies is completely dependent on the pores' distribution patterns. Also, increasing in externally applied voltage to the piezoelectric facesheets, leads the results to enhance. The outcomes of this work can help to design and create smart structures and systems such as sensors and actuators.