by Erin Larsen
A team of engineers at Ohio State University are looking to nature to redesign windmills. In a recent issue of the Journal of Sound and Vibration, OSU researchers reported that they have discovered new information about how vibrations pass through trees when they sway in the wind. They believe that this research can be used to design new tools for harvesting wind energy that look less like windmills and more like mechanical trees.
These tree-like structures would aesthetically be very simple, just a trunk with a few branches. Electromechanical materials would convert random forces intro structural vibrations that generate electricity. This technology may prove most useful on the small scale when other renewable energy sources such as solar are not a good fit, says project leader Ryan Harne, assistant professor of mechanical and aerospace engineering at Ohio State. Potential applications of the technology would include powering sensors used to monitor structural integrity and health of civil infrastructure. Harne envisions these trees taking advantage of the abundant vibrational energy that surrounds us every day and feeding voltages to sensors on the underside of a bridge. The structural monitoring systems would be powered by the same vibrations they are monitoring making them self-sufficient.
Despite how relatively straightforward the idea is, until now, researchers have not made a concentrated effort to capture ambient vibrations. The main deterrent was the assumption that the vibrations generated by nature would not be consistent enough or at a low enough frequency to produce the oscillations useful for electrical energies. Harne used mathematical modeling to demonstrate that it is indeed possible for tree-like structures to control random, high frequency forces. Harne determined that internal resonance could be exploited to covert strong, external vibrations into large amplitude, low frequency vibrations capable of generating energy.
This research paves the path towards more innovative, self-sustaining energy systems.
Frost Gorder, Pam. “News Room614-292-5962.” Turning Good Vibrations into Energy. Ohio State University, 1 Feb. 2016. Web. 02 Feb. 2016.
“Ohio State University, Turning Good Vibrations into Energy (https://news.osu.edu/news/2016/02/01/shaketree/)”