Application of the Characteristic of the "Response Frequency Conversion" of the Chaotic Vibration to Improving the Resonant Sound Reduction of a Double Panel

In many cases, the noise reduction performance of an acoustic panel is poor at the fundamental resonant frequency because large resonant vibration leads to a high sound radiation level. The research team proposes to use the response frequency conversion induced by chaotic vibration to change the panel response frequency from the resonant frequency to a lower and non-resonant frequency. It is expected that the lower response frequency and smaller non-resonant vibration will lead to lower radiation efficiency and lower sound levels.The research team will produce numerical and experimental results for understanding how to utilize response frequency conversion to improve the resonant sound reduction of a double panel. The results will be useful for acoustic engineering applications. For instance, in Hong Kong, a place with many noise problems, sound insulation panels, which are among the major noise control treatments, are always used for chiller/pump noise reduction in outdoor environments. Thus, a good sound insulation panel is designed to perform well for a wide frequency range and must be easy to maintain. The proposed panel, which can be made of metal or other durable materials and will not require any damping treatment to achieve better sound reduction, will be a suitable acoustic treatment in such situations.