Vibro-acoustic characteristics of floating floor system: The influence of frequency-matched resonance on low frequency impact sound

The low frequency vibro-acoustic characteristics of a massive floating floor with continuous resilient layer are investigated with experimental measurements and numerical simulations using a hybrid FEA–SEA method. The results of the study indicate the occurrence of the in situ resonance of the floating floor system, which could be explained by the frequency matching between bending modes of the floating plate and the vibration isolator. The in situ frequency-matched resonance is considered to result in a sharp rise of the low frequency transmissibility of the vibration isolator and the impact sound. The difference between the in situ and the apparent natural frequency of the vibration isolator is assumed to be due to a reduced mass behavior of the floating floor in association with the base floor. It is inferred in the present work that contributing factors in the in situ frequency-matched resonance such as floating plate dimensions, elastic properties of the plate, and the location of an impact might affect the conventional regime of the single degree-of-freedom vibration isolation model for floating floors. The influence of floating plate dimensions on the occurrence of the in situ frequency-matched resonance might be considered as one of the factors affecting the differences in the low frequency impact sound of massive floating floors between laboratory and field measurements.