Analysis of low frequency sound and sound induced vibration in a Norwegian wooden building

Abstract

Low frequency sound, in addition to the effects of audible sound, contributes to human annoyance and building damage by inducing building vibration. This involves whole body vibration sensing of humans, and therefore frequencies down to a few Hz become important. Here, the results of a study of low frequency sound and its generation of building vibration and induced indoor sound is presented. The study is conducted by combining both full scale field tests and numerical simulations. It is shown that the low frequency sound interaction with the fundamental frequencies of the building components combined with air leaks in the building envelope are the main factors that govern transmission of sound into the building. Furthermore, radiation from vibrating ceiling and walls seems to be the dominant source of the low frequency indoor sound, and floor vibration is acoustically driven by the indoor sound pressure in the room. Due to the low frequencies in question, tools to predict sound and vibration, and design mitigation measures at low frequencies noise and vibration in building structures are virtually non-existent. To this end, a finite element model combining acoustic wave propagation and structural dynamics presented in this paper provides a first step. Using this model, a number of countermeasures has been tested and some proven effective in this low frequency range. © 2011 Institute of Noise Control Engineering.

Simulating Low Frequency Sound Transmission Loss of Mounted Panels

“…When it comes to acoustic treatment in rooms there are also a lot of misconceptions among the general public. Full scale tests reveal that when noise transmission occurs inside a building, the peaks of the low frequency sound spectrum are of the same order as the fundamental acoustic room-modes [3], leading to a collection of resonances, which compromise the measurements. International standards describe procedures to extend the measurement range down to the 50 Hz one-third octave band [4,5,6].…”

“…Prescriptions include use of specific source and receiver positions, however the procedure is complex, with the worst case scenario to propose the use of a sufficiently large number of source-receiver combinations as a means to smooth the large spatial variations in measured levels. Moreover, regarding the laboratory geometry, large rooms with volumes V > 200m 3 and specific room size ratios are suggested when low frequency measurements are conducted. Recently, Ayr et al [7] presented a detailed low frequency qualification procedure for a typical reverberant test room in order to perform sound power measurements, by taking advantage of a room finite element model.…”

Influence of Wall Surface and Air Modelling in Finite-Element Analysis of Sound Transmission Between Rooms in Lightweight Buildings

“…However, for lightweight building structures made of materials such as wood, these methods do not provide a reliable prediction of the sound and vibration levels [3]. As proposed by Løvholt et al [4], three-dimensional finite-element models may be applicable in such assessment.…”

“…To find the sound-pressure level in a given room, the air inside that room must be modeled by acoustic finite elements [4,5], or the structural model must be coupled with, for example, a boundary-element model of the air. In any case, inclusion of the air inside all rooms leads to a very complex and/or large numerical model.…”

Influence of Structural Periodicity on Vibration Transmission in a Multi-Storey Wooden Building

“…FE models have been used for analysis of wooden structures by, among others, Brunskog and Davidsson [5], Løvholt et al [6], Maluski and Gibbs [7], and Fiala et al [8]. For large building structures, a solid FE model will contain millions of degrees of freedom if individual joist and studs are to be modelled in detail.…”