Keywords: finite element method, modular, parametric, building, acoustics, vibration, dynamics.

Transmission of sound and vibrations in the built environment is a nuisance to people working and living in buildings. Noise may come from external sources such as traffic and construction sites. Furthermore, noise may propagate from one location internally in a building to another room within the same building from unbalanced washing machines, home cinema audio systems, footsteps etc.

Assessment of noise propagation in the design of new buildings demands a method for analysis of vibration and sound transmission. For heavy structures built of concrete or masonry, methods based on statistical energy analysis (SEA) have been found to provide results of adequate accuracy within the high-frequency range [1]. The European code EN 12354 [2] has agreed it provides acceptable results regarding the overall sound pressure levels in such buildings. However, at low to medium frequencies and for lightweight structures made of, for example, wooden panels on timber frames, SEA and EN 12354 have several shortcomings. Especially, these methods rely in the assumption that the eigenmodes of the structure should be distributed uniformly over the frequency range. But as a result of the periodicity of the rib stiffening in lightweight structures, pass bands and stop bands occur in the frequency ranges relevant to audible sound and vibration recognisable by the human body.

For vibro-acoustic analysis and the design of lightweight building structures, regarding the low to medium frequency range, this paper proposes the use of finite-element analysis. A modular parametric model is constructed using ABAQUS [3] to allow easy implementation of new panels, materials etc. into the building. To obtain this, the model is constructed with an artificial skeleton of beams having (almost) no structural mass and stiffness. The wall and floor panels are coupled to this skeleton. For simple, preliminary analyses, the model allows the use of isotropic or orthotropic shells representing the individual walls and floors. More detailed analysis can be carried out by the use of macro finite elements obtained by system reduction of rigorous models.

The overall idea and specification of the model are presented in this paper. A number of issues related to modelling of individual wall and floor panels, joints between panels and frames, as well as the accuracy of the formulation and various modelling techniques are discussed in the companion papers, by the authors and their co-workers, included in these conference proceedings.

1

R.J.M. Craik, "Sound Transmission Through Buildings using Statistical Energy Analysis", Gower, 1996.

2

EN 12354-1:2000, "Building Acoustics. Estimation of Acoustic Performance in Buildings from the Performance of Elements. Airborne Sound Insulation between Rooms", European Committee for Standardization, 3rd edition, 2000.

3

Dassault Systèmes Simulia Corp., "ABAQUS Analysis User's Manual Version 6.11.", Providence RI, USA, 2011.

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