AbstractsEngineering

Low frequency flanking sound transmission in lightweight buildings:

by W.N.T. Meijers




Institution: Delft University of Technology
Department:
Year: 2015
Keywords: low frequency; sound; lightweigth
Record ID: 1255973
Full text PDF: http://resolver.tudelft.nl/uuid:85e2cdb2-fc82-423b-8cd0-fa02cac59b5b


Abstract

This thesis researched flanking sound transmission, focusing on lightweight structures and low frequency sounds. Finite elements models have been made to simulate the velocity level difference between two floors, with the goal to understand and improve the flanking sound transmission, Three floor variants were designed with the aim to reduce the bending wave propagation, the main wave form of flanking sound transmission. From the formula for bending wave impedance, it appears that both stiffness and mass have influence. Where the stiffness is for a large part determined by the dimensions of the element. Increasing the difference in bending impedances between elements will decrease the propagation of bending waves, and thus decrease the flanking sound transmission. In the table an overview is given of the results. Results have shown that the velocity level difference can have values as high as 50 dB, which means that the flanking sound transmission can be sufficiently reduced. Lightweight elements make smart use of the characteristics that increase the sound reduction, and the low bending wave speed of small elements make low frequency sounds easier to attenuate. Making them potentially better than heavyweight elements.