Numerical analysis of sound insulation performance of double-layer wall with vibration absorbers using FDTD method

For investigating the detail effects of the vibration absorbers in the cavity of the double-layer wall (DLW), a vibro-acoustic numerical model was developed and the behavior of the system was simulated by the finite-difference time-domain method (FDTD method). By comparing the results for various cases, the mechanism of the vibration absorber in the DLW and the effects of the location side and the distribution patterns of the vibration absorbers on the sound insulation performance of the DLW had been confirmed. The deterioration of the sound insulation performance of the DLW due to the mass-air-mass resonance can be improved by the vibration control. In spite of that, setting the vibration absorbers in the cavity causes the movement of the original resonance to the other frequency band and the occurrence of the second resonance. The problems can be dissolved by the sound absorption of the damping material in the vibration absorber. In the investigation, the changes of the sound insulation performance are low correlated with the conditions of the different location side and distribution patterns of the vibration absorbers in the DLW.