A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Wave motion and sound transmission loss of double walls filled with porous materials
Double walls are widely used for lightweight constructions in buildings and vehicles. To increase their sound absorption, they are often filled with porous materials. Their capability to insulate noise is quantified by the sound transmission loss (STL). Accurate calculations of the STL of double walls are needed for characterising prototypes and built-up structures. A semi-analytical approach to calculate the forced response of structures satisfying convenient boundary conditions is presented. Convenient means that the boundary condition is satisfied by a wave solution together with its companion travelling in the opposite direction. The presented approach is based on a waveguide FEM and a Rayleigh-Ritz procedure. First, the formulation of a waveguide finite element for porous material based on the mixed displacement-pressure weak form is derived. Via the waveguide FEM, the dispersion curves of the porous material are calculated, which provide insights to its wave motions. Then, a Rayleigh-Ritz procedure is applied to calculate the mobility of a porous material and the STL of a double wall lined with porous materials. If the structure satisfies convenient boundary conditions, a complete basis describing its motion is constituted by a trigonometric Fourier series. The mobility calculated with this approach agrees well with a standard FE calculation. The calculation of the STL, which mimics standard STL measurements, compares very well to a measurement found in the literature. A drawback of this procedure is that it is limited to structures having constant properties along one direction. On the other hand, the overall procedure is several orders quicker than standard FE models and spectral element models, and can describe frequency dependent materials at virtually no cost. The waveguide finite element method (WFEM) allows meshing complex geometries and intricate materials and may provide insights to the physics of the structure under-study, which is a welcomed possibility.
Wave motion and sound transmission loss of double walls filled with porous materials
Double walls are widely used for lightweight constructions in buildings and vehicles. To increase their sound absorption, they are often filled with porous materials. Their capability to insulate noise is quantified by the sound transmission loss (STL). Accurate calculations of the STL of double walls are needed for characterising prototypes and built-up structures. A semi-analytical approach to calculate the forced response of structures satisfying convenient boundary conditions is presented. Convenient means that the boundary condition is satisfied by a wave solution together with its companion travelling in the opposite direction. The presented approach is based on a waveguide FEM and a Rayleigh-Ritz procedure. First, the formulation of a waveguide finite element for porous material based on the mixed displacement-pressure weak form is derived. Via the waveguide FEM, the dispersion curves of the porous material are calculated, which provide insights to its wave motions. Then, a Rayleigh-Ritz procedure is applied to calculate the mobility of a porous material and the STL of a double wall lined with porous materials. If the structure satisfies convenient boundary conditions, a complete basis describing its motion is constituted by a trigonometric Fourier series. The mobility calculated with this approach agrees well with a standard FE calculation. The calculation of the STL, which mimics standard STL measurements, compares very well to a measurement found in the literature. A drawback of this procedure is that it is limited to structures having constant properties along one direction. On the other hand, the overall procedure is several orders quicker than standard FE models and spectral element models, and can describe frequency dependent materials at virtually no cost. The waveguide finite element method (WFEM) allows meshing complex geometries and intricate materials and may provide insights to the physics of the structure under-study, which is a welcomed possibility.
Wave motion and sound transmission loss of double walls filled with porous materials
Liu, Hao (author) / Barbagallo, Mathias (author) / Finnveden, Svante (author)
2012
12 Seiten, 4 Bilder, 1 Tabelle, 26 Quellen
Conference paper
English
Sound transmission loss of lightweight double walls filled with polyurethane foam
| Tema Archive | 2000
Active Acoustic Control of Sound Transmission through Double Walls: Simulation Results
| SAGE Publications | 2000
Active Acoustic Control of Sound Transmission Through Double Walls: Simulation Results
| British Library Online Contents | 2000
Sound Transmission through Hollow Brick Walls
| SAGE Publications | 1999
Sound Transmission Through Hollow Brick Walls
| British Library Online Contents | 1999