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Study and Development of an In Situ Acoustic Absorption Measurement Method


There are many unwanted noise sources in our industrialised society. Acoustic noise pollution can be reduced by lowering the radiation of the sound source itself, by reflecting sound towards different directions, by dispersing it, or by absorbing sound energy. Absorbing material packages are used in many applications to attenuate sound because it is sometimes impossible to reduce acoustic emission. Although these samples are extensively used, determination of their absorption properties remains a topic of interest due to the lack of appropriate characterisation techniques. A group of a restricted number of absorbing material package types is analysed theoretically well, but proper examination of the properties of many commonly used package types is too complex. Even though some methods are standardised, available measurement techniques have limitations. At times, their outcomes are inconsistent and conflicting, and do incorrectly reflect the characteristics of the material package after installation. Other measurement methods are unsuitable for certain frequency ranges, for certain material package types or for the way in which they are installed. As existing methods leave room for improvement, there is a demand for a convenient and reliable method to measure sound absorption. This work focuses on the development of a method to determine the acoustic absorption of materials in situ (at the position at which they are used), taking advantage of a combined sound pressure - particle velocity measurement method.


Tijs, E., 2013. Study and development of an in situ acoustic absorption measurement method. PhD Thesis, University of Twente.