In the Society of Damping Technology (SDT) in Japan, the working group on technology for the use of vibration damping materials in buildings is investigating effects of the damping characteristics of the viscoelastic edge support structure on the sound insulation properties of window sashes. Experiments are being conducted (measuring vibration response and sound transmission loss) on the condition that the storage modulus kept constant and the material damping (tan δ) varied for the viscoelastic edges. Under similar conditions to the experiments, the glass plate and edge support structure were modeled in three dimensions using the finite element method, and the vibration response was analyzed using the modal strain energy method (MSE method). Further, we compute sound transmission loss using these modal parameters. We clarified the relationships among the complicated change of the transmission loss in the coincidence frequency range, modal damping, and the viscoelastic edge’s stiffness. From our study, modal damping was changed due to viscoelastic edge’s stiffness. This leads to change of the transmission loss. By calculating vibration response and sound transmission loss using frequency-dependent viscoelastic edge’s stiffness, it is found that the experimental values and calculated values are qualitatively consistent.
Yamaguchi et al. (Wed,) studied this question.