Exponentially Tapered Bimorph Piezoelectric Vibration Energy Harvester.
Reske-Nielsen, Mikkel.
2012
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Abstract: This thesis examines the effectiveness of an exponentially tapered
piezoelectric plate for use as a vibration energy harvester (VEH). Typically piezoelectric
energy harvesters have been designed as cantilever beams or "cymbal" type structures. For
these devices there is a known resonant frequency at which displacement is maximized to
produce maximum power. While this can produce good... read moreresults for applications in which a
device vibrates at a specific frequency, many environmental vibration sources are wide-band
and random. The exponentially tapered plate investigated in this work was 55.88mm in length
and tapered exponentially from an initial width of 9.4mm to a final width of 71.12mm. The
effectiveness of this type of structure was investigated to determine how well this system
functioned as a broadband vibration energy harvester. Experimental and computational
analyses demonstrated the presence of an evanescent cut-off frequency of approximately 3800
Hz below which very little energy is transferred from the input into the plate. The result
of this is very inefficient power conversion at or below this cut-off frequency. Since this
is a critical feature of this type of energy harvester this structure will only be
effective at higher frequencies above the cut-off. The mounting assembly design itself was
shown to accurately model an exponentially tapered plate using a square PZT plate rather
than having to have the PZT custom milled to the desired shape. This greatly reduces the
cost of the materials used and should be considered for use in future research related to
exponentially tapered plates. In addition the experimental results showed that as the
frequency of the input is increased, the amount of energy transmitted around the mounting
structure and therefore into the plate from the sides increased. This makes the mounting
structure more suitable for low frequency experimentation, below 3000Hz.
Thesis (M.S.)--Tufts University, 2012.
Submitted to the Dept. of Mechanical Engineering.
Advisor: Robert White.
Committee: Jason Rife, and Masoud Sanayei.
Keyword: Mechanical engineering.read less - ID:
- xk81jz025
- Component ID:
- tufts:21135
- To Cite:
- DCA Citation Guide EndNote
