6 April 2009 Light weight polarized polypropylene foam for noise shielding
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Abstract
The high levels of noise generated during launch can destroy sensitive equipment on space craft. Passive damping systems, like acoustic blankets, work to reduce the high frequency noise but do little to the low frequency noise (<400 Hz). While wall mounted transducers can reduce the low frequency noise during a launch, they also can create areas of higher increased sound pressure in the payload fairings. Ferroelectret cellular polymer foams with high piezoelectric coupling constants are being used as new types of actuators and sensors. Further impedance control through the inverse piezoelectric effect will lead to a new "semi-active" approach that will reduce low frequency noise levels. Combining layers of conventional nonpiezoelectric foam and ferroelectret materials with a multiple loop feedback system will give a total damping effect that is adaptable over a wide band of low frequencies. This paper covers the manufacturing methods that were used to make polarized polypropylene foam, to test the foam for its polarized response and its noise shielding ability.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Travis J. Zelfer, Travis J. Zelfer, Derik S. Warne, Derik S. Warne, Umesh A. Korde, Umesh A. Korde, } "Light weight polarized polypropylene foam for noise shielding", Proc. SPIE 7288, Active and Passive Smart Structures and Integrated Systems 2009, 728820 (6 April 2009); doi: 10.1117/12.815254; https://doi.org/10.1117/12.815254
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