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Noise Reduction Potential of Cellular Metals
Institute for Materials, TU Braunschweig, Langer Kamp 8, Braunschweig D-38106, Germany
* Author to whom correspondence should be addressed.
Received: 15 April 2012; in revised form: 29 May 2012 / Accepted: 7 June 2012 / Published: 12 June 2012
Abstract: Rising numbers of flights and aircrafts cause increasing aircraft noise, resulting in the development of various approaches to change this trend. One approach is the application of metallic liners in the hot gas path of aero-engines. At temperatures of up to 600 °C only metallic or ceramic structures can be used. Due to fatigue loading and the notch effect of the pores, mechanical properties of porous metals are superior to the ones of ceramic structures. Consequently, cellular metals like metallic foams, sintered metals, or sintered metal felts are most promising materials. However, acoustic absorption depends highly on pore morphology and porosity. Therefore, both parameters must be characterized precisely to analyze the correlation between morphology and noise reduction performance. The objective of this study is to analyze the relationship between pore morphology and acoustic absorption performance. The absorber materials are characterized using image processing based on two dimensional microscopy images. The sound absorption properties are measured using an impedance tube. Finally, the correlation of acoustic behavior, pore morphology, and porosity is outlined.
Keywords: acoustic absorption; porosity; pore size; impedance tube
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MDPI and ACS Style
Hinze, B.; Rösler, J.; Lippitz, N. Noise Reduction Potential of Cellular Metals. Metals 2012, 2, 195-201.
Hinze B, Rösler J, Lippitz N. Noise Reduction Potential of Cellular Metals. Metals. 2012; 2(2):195-201.
Hinze, Björn; Rösler, Joachim; Lippitz, Nicolas. 2012. "Noise Reduction Potential of Cellular Metals." Metals 2, no. 2: 195-201.