This Small Business Innovation Research Phase I project is aimed at developing micro-slit panel (MSP) sound absorbers that are effective over broad frequency ranges. MSP absorbers are reclaimable, non-combustible, and environmentally friendly. Traditional absorbers like foams and fibers deteriorate over time and trap oil and other contaminants. On the other hand, MSP absorbers are made from aluminum and plastic, with sound being attenuated due to viscous friction in the sub-millimeter size pores. The panels are separated from a hard surface and are most effective when the acoustic particle velocity is high in the slits. Previous work has demonstrated the viability of the materials in particular frequency bands. However, MSP absorbers will need to be effective over a broader frequency range in order for them to be used in a wider range of applications. The goal of the proposed work is to conduct measurement and numerical simulation studies aimed at improving the MSP performance by varying the slit size and porosity across a panel, and by designing a substrate that can be placed behind the panel. It is anticipated that the developed MSP absorbers will replace foams and fibers in many commercial applications. The broader impact/commercial potential of this project will be the development micro-slit panel (MSP) absorbers that are superior to traditional fiberglass and foam absorbers. Conservative estimates for the potential volume of the product, if it were to be accepted by the architectural community, would be 20 million square feet per year. Areas of application would include ceiling deck panels in airports, train stations, bus terminals, and acoustical ducting in commercial buildings. These products would be especially advantageous in the health and food processing industries because they can be sterilized and cleaned. The materials would also benefit the automotive industry due to their light weight and reclaimability. Typical automobiles have over 50 kg of sound or vibration absorbing material. Using MSP absorbers would reduce this weight, improving fuel economy
