Energy harvesting, an eco-friendly technology, extends beyond solar and wind power in generating electricity from unused or discarded energy in each day life, including vibrations generated by passing automotive engines or trains. Recent intriguing research has been announced, aiming to boost the efficiency of energy harvesting using a brand new sort of metasurface that could be reconfigured, resembling the assembly of LEGO bricks.
Professor Junsuk Rho from the Departments of Mechanical Engineering, Chemical Engineering, and Electrical Engineering and PhD/MS student Geon Lee from the Department of Mechanical Engineering at Pohang University of Science and Technology (POSTECH) have joined Professor Miso Kim from the School of Advanced Materials Science and Engineering at Sungkyunkwan University (SKKU) to collaborate on a research project. Together, they developed a multifunctional elastic metasurface that could be freely configured by attaching and detaching components for practical applications. This research was published in one in every of the international journals in materials science, Advanced Science.
Metamaterials are artificially designed structures that exploit the relationships amongst wavelengths to control wave energy resembling light, vibration, and sound. Harnessing this capability in energy harvesting allows for the gathering of elastic waves in piezoelectric components, thereby increasing the efficiency of electricity production. Nonetheless, limitations within the theoretical evaluation of the beams constituting metamaterials confine their operation to a single frequency and restrict their utility to specific purposes, posing challenges for his or her practical application in real structures.
The research team overcame these limitations by employing the Timoshenko-Ehrenfest beam theory as a substitute of the standard Euler-Bernoulli beam theory. What distinguishes the previous is its consideration of the basic characteristics of elasticity, including shear deformation and rotational inertia effects of the beam. This study marks the primary application of this theory to elastic metamaterial research.
The researchers succeeded in interpreting and modeling elastic metamaterials for phase modulation of elastic waves using the Timoshenko-Ehrenfest beam theory. Moreover, they fabricated a brand new sort of Timoshenko-Ehrenfest beam-based reconfigurable elastic metasurface (TREM) able to attaching and detaching multiple structures. The TREM can reconstruct its surface depending on its application, enabling control over various wave phenomena resembling anomalous wave refraction, wave focusing, self-accelerated wave propagation, and total wave reflection across a large frequency range.
Notably, the team’s TREM demonstrated outstanding effectiveness in harvesting elastic wave energy, enhancing the electrical output power of piezoelectric components by as much as eight times. This highlights its value as a piezoelectric energy harvesting system.
Professor Junsuk Rho, the lead researcher, stated: “I imagine that our newly developed metasurface, designed to operate across multifunctional and wide-frequency ranges, will prove invaluable in energy harvesting, most notably within the eco-friendly utilization of ambient energy. This technology, together with its applications in structural health monitoring, wireless sensing, and the Web of Things, holds great potential for significant contributions across diverse fields.”
This work was supported by the N.EX.T. Impact Project of POSCO Holdings, in addition to by funding from various programs including the Pioneer Research Center Program, the Regional Leading Research Center (RLRC) Program, and the Laboratory for Future Technology Program, all administered by the National Research Foundation of Korea and funded by the Ministry of Science and ICT of the Korean government.
