This dissertation is devoted to examine the performance of the distributed actuators and the constraining layer of the active constrained layer damping (ACLD) treatment made of the horizontally/vertically reinforced 1-3 piezoelectric composite (PZC) materials for active control of geometrically nonlinear static deformations and vibrations of isotropic and orthotropic functionally graded (FG) plates. The isotropic FG substrate plate is composed of ceramic and metallic phases. Its material properties are assumed to be graded across the thickness according to a simple power-law distribution. The orthotropic FG substrate plate is a laminated composite plate. Each layer of this FG laminated composite plate is made of the fiber-reinforced composite material in which the fibers are longitudinally aligned in the plane parallel to the top or bottom surface of the layer while the fiber orientation angle varies across the thickness according to a simple power law. Unlike the conventional laminated composite plates, the FG laminated composite plates are constructed in such a way that the continuous variation of material properties across the thickness of the plates is achieved. The analytical solutions of the simply-supported isotropic FG plates integrated with a layer of the horizontally or the vertically reinforced 1-3 PZC material reveal that this layer can efficiently act as the distributed actuator to counteract the nonlinear deformations of the isotropic FG plates caused by the applied mechanical load. Subsequently, static finite element (FE) analyses are carried out to demonstrate the performance of the patches made of the horizontally and the vertically reinforced 1-3 PZC materials as the distributed actuators of the isotropic FG plates. The analytical solutions also reveal that the active control of the nonlinear deformations of the isotropic FG plates using the distributed actuator made of the vertically reinforced 1-3 PZC material is mainly attributed to the vertical actuation by this actuator. The distributed actuators attached to the softest surface of the host FG plates are more efficient than the same bonded to the stiffest surface of the plates for counteracting the geometrically nonlinear deformations of the plates. Emphasis has also been placed on investigating the effect of variation of the piezoelectric fiber orientation angle on the actuating capability of these distribute Key words: Isotropic FG plates; Orthotropic FG plates; 1-3 piezoelectric composite materials; Active constrained layer damping treatment; Nonlinear vibration.