Abstract
Decreasing of sound and vibration global level inside and/or outside the public works equipment’s cabin as well as the reduction the noise pollution or the pollution due to the vibration and mechanical shocks on construction site is an actual matter; the EU countries must harmonize theirs national legislations regarding the environment pollution and the labor protection with the EU Directives. This article presents the problem of experimental testing of some protective composite materials which can simultaneously absorbs the middle and high range frequencies noise and insulates low frequencies noise. At the same time, these materials can damp the vibrations, in order to avoid noise transmission by structure. The article also presents a case study regarding the global level noise reduction and absorption coefficient inside the cabin of the Romanian frontal loader MMT45. The experimental research and the case study were made in the Research Center of Machines, Mechanic and Technological Equipments – MECMET with the help of specialists from Vibration and Acoustic Laboratory of the Research Institute for Construction Equipment and Technology - ICECON S.A. from Bucharest.
Keywords: modular composite materials, global noise level reduction, sound absorption