H-Cavity Metamaterial for Multi-Frequency Vibration Energy Harvesting

This study presents a vibration energy harvesting method through the design of metamaterial cavities with multiple modes. We developed a bandgap metamaterial using an aluminum bow-tie spring model, achieving a wide bandgap from 525 Hz to 3,100 Hz. The introduction of a cavity into the bandgap metamaterial localizes vibration energy at specific frequencies. The proposed H-cavity design provides multiple modes that enable vibration energy localization across three main frequency bands. We demonstrated that tuning the H-cavity's geometric parameters allows for precise control of resonant frequencies. Furthermore, we established that adjusting the side beam length of the metamaterial can enhance cavity mode performance by more than 200 times. Consequently, optimization of the H-cavity's geometric parameters enables effective vibration energy harvesting in the target frequency range of 1,000 Hz to 2,000 Hz, while side beam length adjustment further improves cavity mode efficiency. To reduce production costs, we designed the H-cavity as a detachable component, allowing for vibration energy harvesting at desired frequencies without necessitating a redesign of the entire metamaterial system, thus providing flexibility in application. © 2024 The Korean Society of Mechanical Engineers.