Numerical Prediction of Impact Sound in Dwellings from Low to High Frequencies

A numerical approach is presented to predict the sound radiated by a point-loaded wall or floor to an adjacent room. The vibration field is deterministically modeled in full detail using the finite element (FE) method, while the acoustic field model depends on the frequency range of interest. At low frequencies, the long-wavelength deformation in the room is deterministically modeled with a limited number of degrees of freedom. At higher frequencies, a large number of degrees of freedom is needed to compute the short-wavelength deformation, which is computationally expensive. Moreover, the sound field in the room becomes sensitive to small wave scattering elements, which are seldomly modeled. At higher frequencies, the room is therefore modeled as a pure-tone diffuse reverberant field with statistical energy analysis (SEA), and the mean acoustic power is computed with a rigorous power balance within a hybrid FE-SEA framework. An experimental validation is presented for two cases: a PMMA plate and a concrete floor. The radiated impact sound is predicted by a pure FE-FE approach at low frequencies (50 Hz - 250 Hz) and by a hybrid FE-SEA approach at higher frequencies (250 Hz - 5000 Hz). Good correspondence between predicted and measured sound pressure levels is achieved.