Pilot study on numerical prediction of sound reduction index of double window system: Comparison of finite element prediction method with measurement

Abstract

The development of windows with high sound insulation performance is essential for preventing the infiltration of traffic noise and the leakage of room noise. A numerical prediction is an effective means of reducing sound insulation testing and development costs to develop a quietness window. As a numerical prediction method for the sound reduction index, the finite element method (FEM) is useful in dealing with structure-acoustic problems. This study was conducted as a pilot study toward developing an accurate numerical model to predict the sound reduction index of a double window. We discussed the accuracy of an FEM model for predicting the diffuse incidence sound reduction index of double windows through a comparison with measured values for a simplified realistically scaled double window. The FE results were compared with measured ones for eight cases with and without a frame absorber. Results showed that the best match to measured values is obtained when using a frame absorber in all the perimeters inside the air cavity. Also, a better agreement is obtained at frequencies of 160-2,000 Hz in other cases. However, a marked discrepancy is found at frequencies above 2,000 Hz and below 160 Hz. Possible reasons for the discrepancies are also discussed.

Finite element modeling for predicting sound insulation of fixed windows in a laboratory environment

“…For the diffuse field incidence condition, we set the sample number as 40. This sample number choice is based on results obtained from our earlier work (Mimura et al, 2022a), where the deviation in SRI on the use of this sample number from 100 sample number results was only 0.3 dB. In the numerical window model, screws are represented by clamped boundary conditions as a support condition (SPC).…”

“…A comparison with measured results revealed the importance of detailed modeling in the structural connection to obtain a better agreement of SRIs between the simulations and measurements. Mimura et al (Mimura et al, 2022a) predicted SRIs of a scale model of a double window using FEM at 100 Hz to 5 kHz. Also, a comparison between FEM results and measured SRIs was made in cases with and without frame absorbers.…”

Predicting Acoustic Performance of Windows with High Sound Insulation

“…A comparison was also carried out between simulated and measured sound insulation values for double-glazed windows with absorbing material between the panes. [9]. The influence of the insulation and the design of the window frame on the insulation of the window was also examined [10].…”

Sound insulation characteristics of small fixed windows in a laboratory and prediction with an existing theory

“…Accurate prediction of the sound insulation performance of windows is an important topic because a window is an essential building component affecting the indoor sound environment of dwellings. Although some theories [1,2] have been used to predict the sound reduction index SRI of single plates, wave-based vibroacoustic numerical analysis [3] can be used for accurate assessment of airborne and structureborne sound propagation for windows of various types with a complex frame structure under appropriate numerical modeling. Nevertheless, even for fixed windows, which are the simplest window type, having a single glass and a simple frame structure, the predictive accuracy of numerical analyses has not been examined in detail because insufficient measured data are available for use as a reference for numerical analysis.…”