Numerical analysis of the influence of acoustic resonance in air cavities between windowpanes on sound transmission loss

The phenomenon of mass-air-mass resonance between multiple panes of a window degrades the noise insulation performance. In this study, a prediction method for the effect of this resonance is proposed by using the boundary integral equation method (BIEM) and its countermeasure by a sound-absorbing treatment for the perimeter of the air cavity on the insulation performance are also discussed. Additionally, the purpose of this paper is to explain the detail of the analysis for prediction of sound transmission of double-pane windows, and to expand this method to triple-pane windows. For simplicity in the analysis and to make clear both the phenomenon of mass-air-mass resonance and the effect of its countermeasure, each pane is modeled as a limp panel that depends only on the mass law, therefore neither the modal effect nor coincidence effect due to elasticity of each pane is considered. In this study, the effect of pane size on sound transmission is evaluated by using the same limp-panel model of infinite extent, which has the essence of mass-air-mass resonance and may express the effect of the phenomenon noticeably.