A New Vacuum Activated Damping Device to Reduce Noise and Vibration During Riveting

Abstract

An actual part of an airplane fuselage was mounted on a jig in an anechoic chamber in order to evaluate, among other things (see paper of P.E.boileau and Al. ), the performance of a vacuum-activated damping device called Vac Damps (damping material glued on aluminium back plate with a rubber seal all around that plate, in order to fix it on the fuselage by means of a partial vacuum underneath). Riveting with 4 mm diameter rivets requires two operators: a "riveter", handling the rivet hammer and a "bucker",pushing on the reaction "bucking bar" to upset the rivet. The first goal of this study was to evaluate the noise attenuation provided by two Vac-Damp panels fixed one above and one below a row of rivets. The other goal was to assess the overall efficiency of such a device in lowering the exposure to hand-arm vibrations, mainly at the "bucker’s" hand. Differences established on a LeqA basis between data with and without the two Vac-Damp have shown an attenuation of about 5 dBA on the global noise radiated at both "riveter’s" and "bucker’s" ears. Furthermore, the hand-arm vibrations on the handle of the rivets gun, and mainly on the "bucking bar" held by the " bucker" ,have also been reduced by approximately 2 to 3 dB through the use of the Vac-Damp panels. We should emphasize that for this particular study, only the radiated noise attenuation was considered. For more information on hand-arm vibration attenuation see ref. ,