Investigation of wooden floor junction in terms of sound wave propagation

In modern building construction, where light weight structures are preferred for cost reasons, the sound transmission is often a problem to be considered carefully, hence the many studies addressing this issue. Various modal methods are frequently used to investigate the vibration pattern of light weight building structures in the low frequency range. The experimental determination of time average transmission and reflection coefficient has been developed for a wooden floor. In this investigation the wave approach is combined with the continuity equation. By doing so, both the flexural wave propagation and the in-plane wave motion can be taken into account. The mismatch impedance is also an important factor, since there is a change of material at the junction, and is therefore included in this study. The scattering matrix formulation is used to separate the transmitted wave and the reflected wave as the structural wave propagates towards a junction, but also to calculate the corresponding transmission and reflection coefficients. One type of junction has been studied with the help of accelerometer matrices: the T junction of a floor structure, together with its reinforcement beams. The experimental results are presented and commented.