Numerical analysis on an annular bimorph piezoelectric power harvester with the out-of-plane vibration mode

This paper proposes a piezoelectric annular bimorph power harvester (PABPH) aiming at scavenging mechanical vibration energy exists in the ambient environment. Abundant energy of the ambient vibration mainly contains in low frequency. In order to decrease the resonate frequency and miniaturize the device, finite element model is present for the harmonic and modal analysis of the PABPH. Numerical results show that maximum of the output power density of the PABPH does not always appear on its first resonance frequency. The resonance frequency depends on the structure parameters of the PABPH, such as the length and the thickness. After being optimized on length of annular plate and thickness of metal layer, the PABPH has an output power density of 36 μW / cm³ when driven by ambient vibration with amplitude of 1mN and frequency of 50 Hz.