Numerical investigation on a bistable vibro-impact dielectric elastomer generator mounted on a vibrating structure with ultra-low natural frequency

Harvesting vibration energy arising from the vibrating structures with ultra-low natural frequencies such as bicycle or automobile body vibrations, human body vibrations, wind turbine oscillations, etc. has always been a challenge, but could enable many potential self-powered sensing applications. To address this issue, a bistable vibro-impact dielectric elastomer generator (BVI DEG) is designed and mounted on a vibrating structure with ultra-low natural frequency to scavenge vibration energy transferred from the vibrating structure. The designed BVI DEG mainly consists of a vibro-impact (VI) DEG, two identical pre-compressed springs, two identical unstretched elastic strings, and a lightweight cuboid shell. The dynamical analysis model of the vibrating structure with the attached BVI DEG and the electrical analysis model of the BVI DEG are developed. The dynamical behaviors of the BVI DEG are numerically analyzed under the harmonic excitation and its rich dynamical behaviors including chaotic and periodic motions are revealed. The energy harvesting (EH) performance under the harmonic excitation is studied for diverse parameters, including the excitation amplitude and frequency, the natural frequency of the vibrating structure, the mass ratio, the impact distance and the different bistable potential wells. The research results show that the EH performance can be significantly improved by appropriately setting these parameters. Moreover, a further comparative study demonstrates the superiority of the BVI DEG operating in the wider excitation frequency range. This work can help guide the design of the BVI DEG mounted on the vibrating structure to enhance the EH performance of the BVI DEG.