Broadband energy harvesting by using bistable FG-CNTRC plate with integrated piezoelectric layers

In this work, a thermally induced bistable plate made of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) with integrated piezoelectric patches is proposed for broadband energy harvesting. Single-walled carbon nanotubes (SWCNTs) in this nano-composite are assumed to have two kinds of functionally graded distributions in the thickness direction. Based on Hamilton's principle and the first-order shear deformation theory of laminates with considering von Karman geometrical nonlinearity, a finite element (FE) model is developed to predict the energy harvesting performance of the proposed bistable plate. By applying thermal field and harmonic excitation to the plate, the cooling-down process and nonlinear dynamic response are analyzed for the bistable behavior of the plate, respectively. The simulation results are validated through comparing with the results obtained from the commercial FE software package ABAQUS. The developed FE model is then used to predict the open-circuit voltages for the proposed bistable energy harvester under different excitation levels. Frequency response diagrams of the root mean square (rms) voltage for the plates with and without bistability are simulated and compared. It is found that bistable FG-CNTRC plates can operate over a wide range of frequencies with delivering higher power than their linear counterparts. Effects of volume fractions and distribution types of SWCNTs on the dynamic behaviors of FG-CNTRC plate are also discussed. It is demonstrated that FG-CNTRC plates show different dynamic characteristics when changing CNTs volume fractions and distributions in it.