Structural modelling of a compliant flexure flow energy harvester

Abstract

CHATTERJEE, PUNNAG. Structural Modeling of a Compliant Flexure Flow Energy Harvester. (Under the supervision of Dr. Matthew Bryant). This thesis presents the concept of a flow-induced vibration energy harvester based on a one-piece compliant flexure structure. This energy harvester utilizes the aeroelastic flutter phenomenon to convert flow energy to structural vibrational energy and to electrical power output through piezoelectric transducers. This flexure creates a discontinuity in the structural stiffness and geometry that can be used to tailor the mode shapes and natural frequencies of the device to the desired operating flow regime while eliminating the need for discrete hinges that are subject to fouling and friction. An approximate representation of the flexure rigidity is developed from the flexure link geometry, and a model of the complete discontinuous structure and integrated flexure is formulated based on transfer matrix method. The natural frequencies and mode shapes predicted by the model are validated using finite element simulations and are shown to be in close agreement. A proof-of-concept energy harvester incorporating the proposed flexure design has been fabricated and investigated in wind tunnel testing. The aeroelastic modal convergence, critical flutter wind speed, power output and limit cycle behavior of this device is experimentally determined and discussed.

Aeroelastic-photovoltaic ribbons for integrated wind and solar energy harvesting

“…Exploiting aeroelastic vibration phenomenon to harvest energy from ambient airflow has been the subject of considerable interest recently [4][5][6][7][8][9]. It has been shown that aeroelastically excited oscillators can have competitive efficiencies and power densities with similarly sized traditional electromagnetic turbines at low operating wind speeds [10], and can offer the additional benefits of simple, solid-state construction.…”

Development of a Nonlinear Piezoelectric Energy Harvester for Alternating Air Load

“…Fluidic energy is a kind of clean energy, such as compressed air and waves. Compressed air energy has attracted great attention due to its kinetic energy induced by piezoelectric materials [12][13][14][15]. Bryant et al demonstrated a sealed spaced array of aeroelastic flutter energy harvesters, and the experimental result showed that the harvesters can extract additional energy from the wake of upstream harvesters, causing larger oscillation amplitudes and higher power output in the trailing devices [16].…”