| || Constrained layer dampers for attenuation of structural vibration
Author : Manoj, N. R.;Barman, S.;Chandrasekhar, L.;Chakraborty, B. C.;Ramesh, R.;Vishnubhatla, R. M. R.
Source : Defence Science Journal ; Vol:55(1) ; 2005 ; pp 5-11
Subject : 623.8 Naval Science
Keywords : Constrained-layer damping system;CLD system;Viscoelastic materials;Structural vibration;Fibre reinforced plastic;Vibration attenuation;Free layer damping system
Abstract : In a constrained-layer damping system, a thin layer of a viscoelastic material is applied over the vibrating substrate and covered with a stiff constraining layer of a metal or a fibre-reinforced plastic. Several viscoelastic materials based on elastomeric blends of copoly (acrylonitrile-butadiene) and polyvinyl chloride were developed. These materials were characterised for hardness, tensile properties, ozone resistance, and electrical and dynamic mechanical properties. Two polymer compositions were used to fabricate 1 mm sheets. The sheets were fixed on an aluminium substrate with a rigid epoxy glue. A fibre-reinforced plastic sheet of 300 m was fixed on the viscoelastic layer by a rigid epoxy glue. The experimental setup for the measurement of vibration response has been elaborated. The study was carried out with and without the constrained-layer damping system. The vibration attenuation achieved was to a minimum of 5-7 dB at 200-500 Hz and to a maximum of 9-16 dB at 3000 - 4000 Hz for the selected constrained-layer damping system.