Resonant frequency of mass-loaded membranes for vibration energy harvesting applications

Vibration based energy harvesting has been widely investigated to target ambient vibration sources as a means to generate small amounts of electrical energy. While cantilever-based geometries have been pursued frequently in the literature, here membrane-based geometries for the energy harvesting device is considered, with the effects of an added mass and tension on the effective resonant frequency of the membranes studied. An analytical model is developed to describe the vibration response for a circular membrane with added mass structure, with the results closely agreeing with finite element simulation in ANSYS. A complementary study of square membranes loaded with a central mass shows analogous behavior. The analytical model is then used to interpret the experimentally observed shift in resonance frequency of a circular membrane with a proof mass. The impact of membrane tension and central proof mass on the resonant frequency of the membrane suggests that this approach may be used as a tuning method to optimize the response of membranebased designs for maximum power output for vibration energy harvesting applications.