Electromechanical study of graphene reinforced lead-free functionally graded tile for vibration energy harvesting

This study focuses on the electromechanical analysis of functionally graded graphene reinforced piezoelectric composite (FG-GRPC) structures in order to identify circuit metrics such as voltage and power. The graphene platelets (GPLs) scatter evenly and parallelly in each graphene platelets reinforced piezoelectric composite (GRPC) tile. The effective modulus of elasticity for the GRPC tile is calculated by the Halpin-Tsai (HT) parallel model. The rule of the mixture (ROM) is employed to estimate the effective mass density, poisson’s ratio, and piezoelectric properties of GRPC structure. A simple power law distribution is responsible for the spatial disparity in composition over the thickness to generate FG-GRPC structural tiles. The first-order shear deformation theory and Hamilton’s principle are used to derive the governing finite element equations for the FG-GRPC plates. The impact of external resistance, frequency, volume fraction, piezoelectric characteristics, and geometry of the tile on the circuit metrics of FG-GRPC structures are thoroughly examined. Our results reveal that the circuit metrics of FG-GRPC plates are significantly enhanced due to consideration of material grading exponent and a small quantity of GPLs. This article will provide the necessary physical insights for modeling the electromechanical coupling in multipurpose piezoelectric materials, devices, and large-scale systems, allowing them to be used in industrial applications such as pressure sensors, miniature ultrasonic motors, fuel injectors, active controllers, and robotic systems.