Abstract
There have been increasing environmental problems caused by low-frequency noise: window rattle, human annoyance and so on. Sound transmission from outdoor into a house in the low-frequency range is a considerably complex phenomenon because the house behaves as a total vibrating system composed of windows, walls, frames, ventilation holes, and so on. This paper presents a finite element model of a simple house in order to investigate the low-frequency sound transmission. The features of the model are as follows: 1) a rigid hollow cube with an aperture on its one side is placed on a rigid plane, 2) a windowpane mounted on the aperture is modeled as a limp membrane or an elastic plate, 3) the outdoor domain is truncated by perfectly matched layers in order to simulate a semi-free field, and 4) a noise source is supposed to be an air conditioning outdoor unit placed near the house. It is confirmed that the indoor SPL gains mainly due to two resonance systems: one is the global motion composed of indoor air tightness and mass around the aperture, and the other is the series of normal modes excited in a cubic room.
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