A prototype of an innovative metamaterial with unconventional properties uses electrical signals to control the direction and intensity of energy waves passing through a solid body. This innovative metamaterial, characterized by a strange mass density, represents a deviation from Newton’s second law, because force and acceleration do not go in the same direction. Huang envisions wide-ranging applications from military and commercial purposes, such as controlling radar waves or managing vibrations from air turbulence in aircraft, to civilian purposes such as monitoring the health of structures such as bridges and pipelines.
University of Missouri researchers have designed a prototype of a small, lightweight active “metamaterial” that can control the direction and intensity of energy waves.
Professor Guoliang Huang of the University of Missouri has developed a prototype metamaterial that can control the direction and intensity of energy waves using electrical signals. The innovative material has potential applications in the military and commercial sectors and can also be used to monitor the structural health of bridges and pipelines.
For more than 10 years, Guoliang Huang, the Huber and Helen Croft Chair in Engineering at the University of Missouri, has explored the unconventional properties of “metamaterials” — a man-made material that exhibits properties not normally found in nature, as defined by Newton’s laws of motion — in his long-term quest to create an ideal metamaterial.
Huang’s goal is to help control “elastic” energy waves traveling through larger structures — such as an airplane — without light and small “metastructures.”
The metamaterial prototype uses electrical signals carried by these black wires to control both the direction and intensity of energy waves passing through a solid material. Credit: University of Missouri
“For many years, I have been working on the challenge of how to use mathematical mechanics to solve engineering problems,” Huang said. “Conventional methods have many limitations, including size and weight. So, I have been researching how we can find an alternative solution using a lightweight material that is small but still able to control low frequency vibrations coming from a larger structure such as an aircraft.
Guoliang Huang. Credit: University of Missouri
Now Huang is one step closer to his goal. In a new study published in Proceedings of the National Academy of Sciences (PNAS) on May 18, Huang and colleagues have developed a prototype metamaterial that uses electrical signals to control both the direction and intensity of energy waves traveling through a solid material.
Potential applications of his innovative design include military and commercial purposes, such as controlling radar waves by directing them to scan a specific area for objects, or managing vibrations created by air turbulence from an aircraft in flight.
“This metamaterial has a strange mass density,” Huang said. “So force and acceleration do not go in the same direction, thus providing us with an unconventional way to customize the design of an object’s structural dynamics or properties to challenge Newton’s second law.”
This is the first physical realization of strange mass density, Huang said.
“For example, this metamaterial could be useful for monitoring the health of civil structures such as bridges and pipelines as active transducers, helping to identify any potential damage that may be difficult to see with the human eye.”
Reference: “Active Metamaterials for Realizing Odd Mass Density” By Qian Wu, Xianchen Xu, Honghua Qian, Shaoyun Wang, Rui Zhu, Zheng Yan, Hongbin Ma, Yangyang Chen, and Guoliang Huang, 18 May 2023. Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2209829120
Other MU collaborators include Qian Wu, Xianchen Xu, Honghua Qian, Shaoyun Wang, Zheng Yan, and Hongbin Ma. Grants from the Air Force Office of Scientific Research and the Army Research Office funded the research.
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