Comparison of viscous and structural damping models for piezoelectric vibration energy harvesters

This work compares viscous and structural damping in a lumped-parameter model of a piezoelectric vibration energy harvester. The dynamic response and power harvested are solved in closed-form for devices with combined viscous and structural damping. The results are then reduced to get expressions for isolated cases of viscous and structural damping. The conditions that maximize the power harvested are determined. These devices generally have two maxima. One maximum is not sensitive to the damping model. The other maximum, however, has meaningful differences between viscous and structural damping models. The differences between the two models increase with increasing electromechanical coupling.