Damping Response Analysis of Sound Absorbing Double Wall Structure with Acoustic Black Holes Including Viscoelastic Layer

Abstract

Numerical analysis is performed to obtain damping responses for double wall structures inserted sound absorbing material. The cover plate of the double wall structure has an acoustic black hole with residual thickness. The boundary at the opposite side of the black hole is fixed. This double wall structure and the acoustic black hole were modeled and numerically analyzed by FEM. Using the MSKE method proposed by Yamaguchi et al., we computed the vibration reduction and changes in vibration transmission of an acoustic black hole with residual thickness. By giving the residual thickness, in the lower frequency band, larger damping effects of the acoustic black hole for the base plate were obtained. However, less damping effects were appeared in the base plate where no acoustic black hole exist.