Efecto de la rigidez dinámica de bandas elásticas en el índice de reducción vibracional en un modelo a escala mediante holografía acústica de campo cercano

Abstract

The Basic Document of protection against noise has introduced one changes very important in the need to install strips of elastic material in the junctions to interrupt the transmission of vibrations at the junctions of a partition with floor, ceiling and partitions . The main acoustic feature of these layers is the dynamic stiffness. At the DB-HR suitable materials for the bands who have a dynamic stiffness, less than 100 MN/m3 are considered, and for floating floors less than 30 MN/m3. To evaluate the flanking transmission, it is determined the the theoretical vibrational reduction index based on UNE-EN 12354. The improving of the interlayer on the rigid juntion, is characterized by a frequency dependent elastic modulus, which indicates the rigidity of the material, and of the thickness of the flexible element interposed. In this case, the theoretical expressions are valid for a certain relation between the Young's modulus and thickness of the layer. This paper evaluates the dynamic stiffness of elastic layers in juntions by an inverse method. Vibration reduction index is obtained by Nearfield Acoustic Holography in a scale model. Linear adjustments are obtained that describe the behavior and allow to obtain a range of dynamic stiffness of the elastic layers.