Remotely Moving Objects Underwater Using Sound #ASA188

Acoustic metamaterial enables pushing, rotating, and more complex movements in 3D.

Media Contact:
AIP Media
301-209-3090
media@aip.org

NEW ORLEANS, May 20, 2025 – Sound can do more than just provide a nice beat. Sound waves have been used for everything from mapping the seafloor to breaking apart kidney stones. Thanks to a unique material structure, researchers can now move and position objects underwater without ever touching them directly.

Dajun Zhang, a doctoral student at the University of Wisconsin-Madison, will present his work on developing a metamaterial for underwater acoustic manipulation Tuesday, May 20, at 3:20 p.m. CT as part of the joint 188th Meeting of the Acoustical Society of America and 25th International Congress on Acoustics, running May 18-23.

The metamaterial created by Zhang is used to push and rotate an object adorned with the University of Wisconsin’s Bucky the Badger. Credit: Dajun Zhang

A metamaterial is a composite material that exhibits unique properties due to its structure. Zhang’s metamaterial features a small sawtooth pattern on its surface, which allows adjacent speakers to exert different forces on the material based on how the sound waves reflect off it. By carefully targeting the floating or submerged metamaterial with precise sound waves, Zhang can push and rotate any object attached to it exactly as much as he wants.

Manipulating objects in water without touching them could make a lot of underwater work easier. It could also be used inside the human body, which is mostly water, for applications like remote surgery or drug delivery.

“Our metamaterial offers a method to apply different acoustic radiation forces on objects in liquid media, such as underwater robots and vehicles, parts for assembly, or medical devices and drugs,” said Zhang.

However, manufacturing underwater metamaterials with the correct properties for object manipulation is difficult, especially with conventional methods.

“Current fabrication methods for underwater metamaterials do not provide the resolution or material properties required and are usually very expensive,” said Zhang. “To solve this issue, I developed a new fabrication method. This method is not only low cost and easy to implement but also achieves high fabrication resolution and large acoustic impedance contrast with water, which are keys to underwater metamaterials.”

In tests, Zhang used his metamaterial to manipulate floating objects, such as wood, wax, and plastic foam, along with objects completely submerged underwater. He attached his metamaterial to each object and used acoustic waves to push, pull, and rotate them. With submerged objects, this technique gave him the ability to manipulate them in three dimensions.

Zhang plans to continue his work, developing a metamaterial patch that is smaller and more flexible. He hopes his work will lead to new uses in medicine and underwater robotics.

“Our research opens new opportunities for both underwater acoustic metamaterials and remote manipulation,” said Zhang. “Acoustic metamaterials and metasurfaces can now be used to generate forces remotely for underwater or in-body levitation, actuation, and manipulation applications.”

——————— MORE MEETING INFORMATION ———————
Main Meeting Website: https://acousticalsociety.org/new-orleans-2025/
Technical Program: https://eppro01.ativ.me/src/EventPilot/php/express/web/planner.php?id=ASAICA25

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting and/or press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE INTERNATIONAL COMMISSION FOR ACOUSTICS
The purpose of the International Commission for Acoustics (ICA) is to promote international development and collaboration in all fields of acoustics including research, development, education, and standardization. ICA’s mission is to be the reference point for the acoustic community, becoming more inclusive and proactive in our global outreach, increasing coordination and support for the growing international interest and activity in acoustics. Learn more at https://www.icacommission.org/.

Reducing Underwater Noise When Installing Subsea Structures #ASA188

Constructing offshore windfarms is loud and disruptive to marine life.

Media Contact:
AIP Media
301-209-3090
media@aip.org

NEW ORLEANS, May 20, 2025 – Offshore wind farms have the potential for large impacts on clean energy generation, as wind speeds are higher at sea than on land. However, this benefit comes at a high cost for marine life, which can suffer greatly during the installation of offshore wind foundations.

Junfei Li, from Purdue University, will present work on mitigating the noise pollution during monopile offshore wind farm installation Tuesday, May 20, at 1:00 p.m. CT as part of the joint 188th Meeting of the Acoustical Society of America and 25th International Congress on Acoustics, running May 18-23.

This metamaterial structure is made to reduce the noise pollution from undersea monopile foundation construction. Credit: Junfei Li

“To build offshore wind farms, monopile foundations are commonly driven into the seabed with hydraulic impact hammers, generating strong noises that propagate 50 kilometers or more from the installation site, potentially inducing auditory injury and behavioral change in marine species,” said Li.

These deep foundations are crucial for physically supporting wind farms — and other structures — above the sea. Most current mitigation techniques are limited by high energy demands or challenges with transportation and deployment.

Li and his colleagues instead developed a metamaterial comprising of carefully arranged plates that trap air within and act as guides for the sound. With their metamaterial in place, sound from monopile installation can be reduced by 40 decibels, an improvement over the 25-decibel reduction of other methods. The material is modular and foldable, making its transport and deployment easy and inexpensive.

Li said the sounds created during these processes have wide-reaching impacts.

“The high-intensity, impulsive noise generated by pile driving has the potential to affect a range of wildlife — including marine and freshwater fish, sea turtles, and marine mammals,” said Li. “It may lead to a range of behavioral changes in marine mammals and may lead to auditory or physical injury in some species of fish.”

The researchers hope to scale up their technology for deployment in future offshore wind far constructions, as well as for monopiles used in bridge construction and oil drilling platforms.

“Human-generated underwater noise is a critical — yet often hidden — environmental stressor. It’s not just background sound; it actively harms marine life, affecting their ability to survive and thrive,” said Li. “We must acknowledge the severity of our acoustic impact on the underwater world and work toward reducing it.”

——————— MORE MEETING INFORMATION ———————
Main Meeting Website: https://acousticalsociety.org/new-orleans-2025/
Technical Program: https://eppro01.ativ.me/src/EventPilot/php/express/web/planner.php?id=ASAICA25

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting and/or press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE INTERNATIONAL COMMISSION FOR ACOUSTICS
The purpose of the International Commission for Acoustics (ICA) is to promote international development and collaboration in all fields of acoustics including research, development, education, and standardization. ICA’s mission is to be the reference point for the acoustic community, becoming more inclusive and proactive in our global outreach, increasing coordination and support for the growing international interest and activity in acoustics. Learn more at https://www.icacommission.org/.

Acoustic Metamaterials for Quality of Life: Engineering Challenges for Low-Height Noise Barriers

Domenico De Salvio – domenico.desalvio2@unibo.it
Instagram: @midrashdds
Department of Industrial Engineering (DIN)
University of Bologna
Bologna, Bologna 40136
Italy

Massimo Garai
Department of Industrial Engineering (DIN)
University of Bologna
Bologna, Bologna 40136
Italy

Popular version of 3pNS3 – Metamaterials application on low-height noise barrier for railways: challenges of real-world scenarios
Presented at the 188th ASA Meeting
Read the abstract at https://eppro01.ativ.me//web/index.php?page=IntHtml&project=ASAICA25&id=3870863

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

If you’ve ever lived near a train line, you know the roar of passing cars can be more than annoying — it can hurt your health. A primary source of this noise comes from transportation; among them, railway lines, having a high density in Europe, can be particularly disturbing for nearby residents. The traditional high noise barriers can help, but they aren’t always practical in urban areas. Low-height noise barriers (LHNBs), typically less than 1 meter high, can be a good alternative. These barriers work well because they can be placed very close to the source of the noise, such as where train wheels interact with the rails, as shown in Figure 1.

Figure 1. A low-height noise barrier is placed next to the railway. Image courtesy of Kraiburg Strail®.

However, for these low barriers to work best, their surface needs to be good at absorbing sound (see Figure 2). Here, acoustic metamaterials can play a key role. These artificial structures have unique properties that natural materials lack, enabling them to absorb sound in ways that conventional materials cannot. Their functionality relies on their geometric configuration rather than solely on the raw materials used, enabling them to be made from weather- and dust-resistant materials.

The effectiveness of an Low-Height Noise Barrier

Figure 2. The effectiveness of an LHNB. The colors represent sound pressure level: red indicates the highest noise levels, while blue shows the lowest. On the left, the noise generated by the wheel-rail interaction. In the middle, the effectiveness of a generic LHNB is shown. On the right, the noise reduction achieved by an optimized sound-absorbing LHNB. The less red there is, the more effective the LHNB is.

This study is part of the European project LIFE SILENT and examines the integration of metamaterials into a specific type of LHNB. It employs two types of acoustic resonators designed within the constraints of a real-world scenario: Neck Embedded Helmholtz Resonators (NEHRs) and Fabry-Pérot (FP) channels. Combining these resonators enables the LHNB to mitigate railway noise.

Designing these complex structures requires a thorough process. The optimal geometry of the metamaterial has been studied through a combination of complex simulations and nature-inspired algorithms. Specifically, the geometry was optimized using a computational technique called “particle swarm” inspired by the social behavior of flocks of birds and schools of fish.

Prototypes of the metamaterial units were 3D printed in plastic because of the need for customization and precision (see Figure 3). Once the efficiency of the metamaterial is tested, serial production of the optimized geometry can also be achieved through traditional industrial molding techniques, thus, in real-world scenarios.

Figure 3. Example of 3D printed metamaterial NEHRs (on the left) and FP (on the right), the units that compose the sound-absorbing LHNB surface.

This work demonstrates how metamaterial engineering can be applied to everyday situations. The study tackles practical limitations and constraints, the need for durability against outdoor conditions, and the challenges of manufacturing complex structures. The research outlines the essential steps to transition from a lab idea to a potentially mass-produced solution against noise pollution by developing a focused design, creating physical prototypes, and conducting tests. While recognizing challenges like manufacturing accuracy and the impact of real-world conditions, the project emphasizes that acoustic metamaterials can be designed to be robust and effective for public infrastructure, paving the way for their practical use for a better daily life.

Reducing Ship Noise Pollution with Structured Quarter-Wavelength Resonators

Mathis Vulliez – mathis.vulliez@usherbrooke.ca

Université de Sherbrooke, Département de génie mécanique, Sherbrooke, Québec, J1K 2R1, Canada

Marc-André Guy, Département de génie mécanique, Université de Sherbrooke
Kamal Kesour, Innovation Maritime, Rimouski, QC, Canada
Jean-Christophe G.Marquis, Innovation Maritime, Rimouski, QC, Canada
Giuseppe Catapane, University of Naples Federico II, Naples, Italy
Giuseppe Petrone, University of Naples Federico II, Naples, Italy
Olivier Robin, Département de génie mécanique, Université de Sherbrooke

Popular version of 1pEA6 – Use of metamaterials to reduce underwater noise generated by ship machinery
Presented at the 186th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0026790

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

The underwater noise generated by maritime traffic is the most significant source of ocean noise pollution. This pollution threatens marine biodiversity, from large marine mammals to invertebrates. At low speeds, the machinery dominates the underwater radiated noise from vessels. It also has a precise sound signature since it usually operates at a fixed rotation frequency. If you think of it, an idling vehicle produces a tonal acoustic excitation. The sound energy distribution is mainly concentrated at a few precise frequencies and multiples. Indeed, the engine rotates at a given rotation speed – in round per minutes – or frequency (divided by 60, it is the number of oscillations per second). In addition to the rotating frequency, the firing order and the number of cylinders will lead to the generation of excitation multiples of the rotating frequency. The problem is that the produced frequencies are generally low and difficult to mitigate with classical soundproofing materials requiring substantial material thickness.

This research project delves into new solutions to mitigate underwater noise pollution using innovative noise control technologies. The solution investigated in this work is structured quarter-wavelength acoustic resonators. These resonators usually absorb sound at a resonant frequency and odd harmonics, making them ideal for targeting precise frequencies and their multiples. However, the length of these resources is dictated by the wavelength corresponding to the target frequency. As for the required material thickness, this wavelength is significant at low frequencies (in air, for a frequency of 100 Hz and a speed of sound of 340 m/s, the wavelength is 3.4 m since the wavelength is the ratio of speed by frequency). The length of a quarter wavelength resonator tuned at 100 Hz is thus 0.85 m.

Fig.1. Comparison between classical and innovative soundproofing material on sound absorption, from Centre de recherche acoustique-signal-humain, Université de Sherbrooke.

Therefore, a coiled quarter wavelength resonator was considered to reduce its bulkiness, and facilitate their installation. The inspiration follows Archimedes’ spiral geometry shape, a structure easily manufactured using today’s 3D printing technologies. Experimental laboratory tests were conducted to characterize the prototypes and determine their effectiveness in absorbing sound. We also created a numerical model that allows us to quickly answer optimization questions and study the efficiency of a hybrid solution: a rock wool panel with embedded coiled resonators. We aim to combine classic and innovative solutions tom propose low weight and compact solutions to efficiently reduce underwater noise pollution!