A Comprehensive Study on Nonlinear Functionally Graded Piezoelectric Harvesters under Moving Loads

The goal in this research was to investigate harvesting energy from a nonlinear functionally graded beam with bonded piezoelectric patch under multiple moving loads. The material of the harvester was considered to be varied in the thickness direction. The generalized Hamilton's principle and von Karman nonlinear theory were used to obtain a coupled system of differential equations considering nonlinear geometry as well as electromechanical coupling. The Newmark time integration scheme as well as the finite-element method were used to obtain the numerical results. Numerical study was also performed to investigate the effects of velocity of the moving loads, time lags between the moving loads, beam length, material distribution, and piezoelectric patch location on the harvested power. Results indicate that the aforementioned parameters have significant effects on the harvested power. The results show that ignoring the nonlinear effects especially for considerable values of moving loads results in erroneous large values for the harvested power. To the best of authors' knowledge, there is no other study about energy harvesting from nonlinear vibrations of beams under moving loads.