주름강판의 차음 성능과 모드 밀도

In a railway vehicle, corrugated steel panel is widely used for the floor structure because of the high bending stiffness per weight. However, corrugated steel panel shows lower sound insulation performance than that of the flat plate with the same weight. Especially, in a particular frequency band, the sound transmission loss significantly decreases. Local resonance is known as the main reason of the sharp decline of the sound transmission loss. Above a certain frequency band, modal density rapidly increases as a large number of local resonance modes occur. In this study, we estimate the sound transmission loss of the corrugated steel panel in respect of the modal density. Modal density of the corrugated steel panel is calculated by finite element analysis and the sound transmission loss is measured based on ASTM E2249-02. The result will be applied to improve the sound insulation performance of the corrugated panels.