"Eco Kyuon" - Microperforated Sound Absorbing Panel

This paper presents the development of sound absorbing panels utilizing the sound absorption mechanism of microperforated plates and foils. Microperforated plates and foils reduce acoustic energy by generating friction damping and pressure loss from the vibration of acoustically resonating aperture air. Applying this principle, we have developed a method to predictively calculate the sound absorption coefficient and applied it to develop microperforated sound absorbing panel products. A distinct advantage of this method is that these products can be designed with the optimum frequency characteristics for the desired sound absorption coefficient. These products were used to develop rail and road noise barriers that contribute to traffic noise reduction. An additional purpose of the study was to develop a transparent sound absorbing panel solution. We selected polycarbonate, a clear polymer material, as the film material to which this technology was applied. The challenge was to overcome the drop in sound absorption due to the propensity of the transparent polymer film to intense vibrations. Improved sound absorption performance was successfully achieved by creating several combinations of manufacturable materials, calculations for predicting the sound absorption coefficient and performance verification experiments. Optimization of design elements such as sheet thickness, aperture diameter, and aperture ratio was also critical to achieving the desired performance. Since successful commercial transparent sound absorbing panels are rare, these products hold much promise for broad application in a variety of markets.