An analytical model is developed based on modified shear deformation theory to study energy harvesting using a piezoelectric layer deposited on functionally graded (FG) beams. The mechanical properties of the beam vary according to the power law in the beam thickness direction. Different shear deformable beam theories including trigonometric, exponential, hyperbolic, and fifth-order shear deformation theory are modelled that can encounter rotary inertia impacts. The harvester is excited at its base, and the response is expressed in the form of translation and rotation. A concentrated mass is applied at the free end of the beam. Two different damping types, Kelvin-Voigt damping and air damping, are assumed separately. The coupled electro-mechanical governing equations of the FG harvester are derived using Hamilton’s principle, and then discretized using the Galerkin approach and diagonalization method to find the electrical characteristics of the harvester. At the end, the effect of geometrical parameters, FG index, and concentrated mass on the extracted voltage and power is evaluated in detail. Furthermore, the size and location of the piezoelectric layer to optimize the electrical output is studied.
