A modified vibration model for piezoelectric energy harvester by considering the joints between adjacent parts

This paper aims at the novel approach to establish the equation of the motion of the piezoelectric energy harvester. The energy harvester is composed of three beams, two masses and two joints. Each joint is modeled as a spring and a damper. Since two of the three beams are identical in geometry and deflection, the device is actually a 2-DOF vibration system with 2 natural frequencies. With comparing to the experimental data, the computed natural frequency without the implantation of the joint can be overestimated by 10.7%. With introducing the joint, the difference between the model and experiments reduces to less than 0.1%. It suggests the necessary of implementation of the joint. The damping of the joint can be obtained by the frequency response comparison between the analytical model and the experimental data.