Effective kinetic energy harvesting via structural instabilities

Abstract

Vibration energy harvesting has been shown as a promising power source for many small-scale applications mainly because of the considerable reduction in the energy consumption of the electronics, ease of fabrication and implementation of smart materials at small scale, and scalability issues of the conventional batteries. However, conventional energy harvesters are not quite robust to changes in excitation or system parameters, suffer from narrow bandwidth, and are very inefficient at small scale for low frequency harvesting. In addition, they have a low power to volume ratio. To remedy the robustness issues, improve their effectiveness, and increase their power density, we propose to exploit structural instabilities, in particular instabilities in multi-layered composites which are inherently non-resonant. The induced large strains as a result of the structural instability could be exploited to give rise to large strains in an attached piezoelectric layer to generate charge and, hence, energy. The regular high-strain morphological patterns occur throughout the whole composite structure that in turn enable harvesting at a larger volume compared to conventional harvesters; hence, harvesting via structural instabilities can significantly improve the harvested power to volume ratio. In this study, we focus on harvesting from wrinkling type of instabilities. Keywords: energy harvesting, instability, wrinkling, vibration, piezoelectric