- Inspired by fish bone structure, realizing innovative noise reduction technology -

UIWANG, South Korea – March 12 – Korea Railroad Research Institute (KRRI) (President: Seok-Youn Han) has developed a Fishbone Silencer modeled after fish bones, applying biomimetic technology. Unlike conventional silencers, this silencer is characterized by high noise reduction effects without using sound-absorbing materials or acoustic absorbents.

Silencers is applied to various fields such as railroad vehicles and tunnels, ventilation ducts, and industrial exhaust systems to reduce noise.

Conventional duct-type silencers used sound-absorbing materials to reduce noise, but they had limitations of being vulnerable to moisture and difficult to maintain. In addition, they were heavy and costly due to the use of many metal materials.

To solve these problems, the KRRI researchers designed internal partitions or splitters in a fishbone shape that reflects noise in a specific direction or induces a weakening effect by bouncing sounds off each other. This enabled noise reduction without the need for sound-absorbing materials.

In particular, researchers applied a scientific approach to precisely analyze the movement of airflow and noise. They derived optimal design by testing various structures through two- and three-dimensional computational analysis, and ensured reliability through experiments at an accredited testing center.

The Fishbone Silencer is an original design inspired by the fishbone structure, the backbone of a fish. The slender structure (Rib) made up of several layers plays a role in dispersing, reflecting, and reducing noise.

Conventional silencers mainly utilize sound-absorbing materials to reduce noise, but they had the disadvantage of deteriorating over time or being difficult to maintain.

The Fishbone Silencer reduces noise effectively even without sound absorbing materials and optimizes airflow to help spread less noise. In addition, the retractable structure allows for easy maintenance, which is expected to reduce costs.

Related Research Projects
- Project name: Development of Railway Noise Optimization Technology Based on Meta and Digital Twin (KRRI Basic Project)
(Research Period: Jan. 2024 ~ Dec. 2026/
Project Manager: Hee-Min Noh, Principal Researcher at KRRI)

According to the performance tests conducted by an accredited testing center, the Fishbone Silencer showed an average noise reduction effect of more than 10dB compared to the conventional method in the 500~5000Hz frequency band.

Furthermore, when reinforced with Thinsulate-type sound-absorbing materials on the exterior, the noise reduction effect was further maximized, and not only was noise reduction performance improved, but airflow was also confirmed to be more than 20% smoother.

Principal Researcher Hee-Min Noh of the KRRI said, “This is an innovative technology inspired by nature, which is differentiated from existing technologies in that it can effectively reduce noise without sound-absorbing materials,” adding, ”We plan to commercialize the Fishbone Silencer with reduced maintenance costs and eco-friendliness and apply it widely to railway vehicles and infrastructure.”

President Seok-Youn Han of KRRI, said, “The development of the Fishbone Silencer is an important example of the advancement of eco-friendly K-railway technology and,” “KRRI will continue to work with governments and railroad operators to further strengthen our research to reduce noise and to innovate sustainable railroad technology.”

※Reference: (Photo) Introduction of In-Duct Fishbone Silencer Technology





Press Contacts

Yoonju YI
Korea Railroad Research Institute
yjyi@krri.re.kr
+82 31 460 5189