Modeling and experimental verification of multi-modal vibration energy harvesting from plate structures

The focus of the present work is on the design of plate structures for vibration energy harvesting from two or more modes of vibration. The work is motivated by the quest to design resonators that respond to variable frequency sources of base excitation. The geometry of two-dimensional structures, such as V-shaped and open delta-shaped plates, is explored to obtain closely spaced harvestable vibration modes to scavenge energy across a broader bandwidth. To this end, an electromagnetic energy harvester in the form of a base excited plate is proposed. The plate carries tip magnets that oscillate past stationary coils to generate power from the lower modes of vibration. The plate dynamic behavior is governed by its geometry and placement of the magnets on its tip. An effort is made to optimize the system configuration so as to control the spacing between the resonance frequencies while efficiently harvesting energy from all modes. Plates possessing three natural frequencies in the range from 8 to 19 Hz are developed, and findings of the present work are verified numerically and experimentally.