Energy harvesting, an environmentally beneficial technique, goes beyond solar and wind power to create electricity from unused or discarded energy in everyday life, such as vibrations caused by passing car engines or trains. A recent study has been announced to improve energy harvesting efficiency by adopting a new type of metasurface that can be modified, similar to how LEGO bricks are assembled.
Image Credit: Pohang University of Science and Technology
Professor Junsuk Rho from the Departments of Mechanical Engineering, Chemical Engineering, and Electrical Engineering, as well as PhD/MS student Geon Lee from the Department of Mechanical Engineering at Pohang University of Science and Technology (POSTECH), have teamed up with Professor Miso Kim from Sungkyunkwan University’s School of Advanced Materials Science and Engineering to work on a research project.
They worked together to create a multipurpose elastic metasurface that can be flexibly customized by attaching and removing components for practical purposes. This study was published in Advanced Science, an international publication for materials science.
Metamaterials are artificial structures that use wavelength relationships to alter wave energy like light, vibration, and sound. Harnessing this capability in energy harvesting enables the collection of elastic waves in piezoelectric components, enhancing the efficiency of energy production.
However, restrictions in the theoretical study of the beams comprising metamaterials limit their functioning to a single frequency and their value to specific applications, providing hurdles for their practical deployment in actual structures.
The study team overcame these constraints using the Timoshenko-Ehrenfest beam theory rather than the standard Euler-Bernoulli beam theory. The former differs because it considers the fundamental properties of elasticity, such as shear deformation and the beam’s rotational inertia. This study is the first to apply this theory to elastic metamaterials research.
The researchers were able to analyze and simulate elastic metamaterials for phase modulation of elastic waves using the Timoshenko-Ehrenfest beam theory. Furthermore, they developed a new type of Timoshenko-Ehrenfest beam-based reconfigurable elastic metasurface (TREM) that can attach and detach various structures.
Depending on the application, the TREM may rebuild its surface, allowing control over various wave phenomena such as anomalous wave refraction, wave focusing, self-accelerated wave propagation, and complete wave reflection over a broad frequency range.
Notably, the team’s TREM was extremely successful in harvesting elastic wave energy, increasing the electrical output power of piezoelectric components by up to eight times. This demonstrates its usefulness as a piezoelectric energy harvesting system.
I believe that our newly developed metasurface, designed to operate across multifunctional and wide-frequency ranges, will prove invaluable in energy harvesting, most notably in the eco-friendly utilization of ambient energy. This technology, along with its applications in structural health monitoring, wireless sensing, and the Internet of Things, holds great potential for significant contributions across diverse fields.
Junsuk Rho, Study Lead Researcher and Professor, Pohang University of Science and Technology
This study was supported by POSCO Holdings’ N.EX.T. Impact Project, as well as funding from various programs such as 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 Korean government’s Ministry of Science and ICT.
Journal Reference:
Lee, G., et. al. (2024) Timoshenko–Ehrenfest Beam-Based Reconfigurable Elastic Metasurfaces for Multifunctional Wave Manipulation. Advanced Science. doi:10.1002/advs.202400090