Some Aspects in Vibration Isolation Analysis.
NAVAL UNDERWATER SYSTEMS CENTER NEWPORT RI
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This report presents the results of an experimental study designed to determine the transmissibility of some elastic and viscoelastic materials which are used in the design and construction of anti-vibration mounts. The object of this investigation has been primarily based on the determination of the material parameters which establish reasonable criteria for effective vibration isolation, namely the dynamic modulus and the damping factor. The experimental determination of these quantities allowed for the evaluation of the transmissibility curves which were obtained by computer techniques. The samples exhibiting elastic behavior i.e., brass, aluminum and stainless steel were chosen and tested for two reasons. The first one was primarily intended to obtain conclusive data supporting some concepts given in governmental technical notes on the design improvement of vibration isolation mounts. The second reason was based on the evaluation of these three metals and the relative effects they would produce on the isolation properties of composite structures. The samples exhibiting viscoelastic properties consisted of urethanes of two different Shore durameters, namely A-15 and A-40. Based on past evaluation of constrained-layer damping, these samples were compared to similar specimens consisting of aluminum honeycomb structures filled with the same viscoelastic compounds. The Bruel and Kjaer complex modulus apparatus and its associated electronic equipment were used to perform this study.
- Metallurgy and Metallography