Dr. Lin Lin
Noise Absorption, Noise Control
An acoustic impedance testing tube is designed and constructed to test noise absorption properties of selected materials. The structure will be made to be convenient for demonstration purposes and real testing procedures while following ASTM E1050 standards as closely as possible. An engineering drawing as well as a 3D-‐CAD model of the structure is developed. Testing is conducted on selected materials; mainly ones that will allow obtained results to be compared to results found by other parties. Various sounds will be generated using Mathematical programming; the types of sound will include single frequency, wide band and narrow band noises. Microphones are used, in conjunction with an oscilloscope or computer, to analyze the sound received on either side of the material in the tube. Through data processing various operations and Fourier transforms are performed on the collected sound data. This processing allows for unique characteristics of the materials to be extracted from the data. This data relates the damping effects of the material as they relate to the power and frequency of the noise. The properties of the materials are compared to published material properties. Based on the results, suggestions and ideas for further testing or redesign are reported. Parts that are used or are to be recommended for use are listed. Example of Results Test
Tarling, Brian, "Noise Control by Structure and Material" (2015). Thinking Matters Symposium Archive. 38.