Controlled elastic instabilities in cylindrical shells for energy harvesting devices

The sudden motion from elastic instabilities is a promising avenue to develop energy harvesting devices for systems with structural response in the quasi-static range (frequency << 1 Hz). Key to the concept is the ability to control the generation of snap-through transitions. This paper introduces the concept of using cylindrical shells as mechanical energy concentrators and frequency modulators for use in energy harvesting devices. Cylinders with Non-uniform Stiffness Distributions (NSD), which have been shown to allow control of their elastic postbuckling response were used. Finite element simulations and pilot experiments on 3D printed shells with PVDF piezoelectric harvesters were conducted to evaluate the concept. Results demonstrated that NSD designs allow for considerably enhanced placement of piezoelectric harvesters over uniform shell designs and consequently increased harvested power. The presented research shows that cylindrical shells with controlled postbuckling response are a viable structural prototype for use in energy harvesting devices.