Indian researchers from IIT Hyderabad have fabricated paper honeycomb and stronger polymer honeycomb structures as sound-absorbing panels that dissipate acoustic energy to low-frequency ranges. The technology can be utilized in building acoustics and for noise management in the environment.
A variety of traditional materials have been discovered to be good at controlling higher frequencies. Natural bee hives, on the other hand, have been discovered to effectively manage both high and low frequencies due to their geometry.
Benefits of the technology:
The conversion of acoustic energy into vibration energy was discovered through theoretical analysis and experimental investigations. Due to the wall dampening property, this vibration energy is dissipated in the form of heat. Engineering a solution that mimics this feature could be a cost-effective way to reduce noise pollution.
Using biomimetic design methodology, Dr. B. Venkatesham and Dr. Surya, faculty at IIT Hyderabad’s Mechanical and Aerospace Engineering Department, developed low thickness and strong acoustic panels that mimicked this feature. Understanding the physics of bee hive sample acoustic energy dissipation and then mimicking the design is part of the design methodology.
The researchers created a mathematical model, determining optimum parameters, and then used systematic, controlled parameters to build the test samples. Following that, a big sample was fabricated. They employed two separate methodologies and prototype machines, as well as two different types of materials.
One prototype is based on the indexed Honeycomb Before Expansion (HOBE) process for paper honeycomb, and another is based on the hot wire approach for polymer honeycomb structures.
Slicing stacked extruded polypropene straws were used to make the panels. The slicing is done with the help of a heated wire, which also serves to connect the straws. The developed method allows for a mechanism of acoustic energy dissipation using acoustic panels of lower thickness and higher specific strength. As part of this project, a test facility for measuring the absorption coefficient of big samples was built.
Technology is in the 6th stage of Readiness Level
This technology is in the 6th stage of the Technology Readiness Level, and Dr. B. Venkatesham has partnered with Eaton PVT Ltd, Maharashtra Industrial Development Corporation Kharadi Knowledge Park, Pune. This technology, supported as part of the Advanced Manufacturing Technologies programme of the Department of Science and Technology (DST), Government of India.
Dr. Venkatesham says that it may create an opportunity to capture 15% of the traditional sound-absorbing acoustic material market based on low-frequency applications. He plans to further scale up the technology demonstration, develop a batch production machine for polymer materials, fabricate with newer alternative self-damping materials, and comply with other safety requirements like flame retarding capacities, weather ability and so on.