Sound radiation from multilayered structures

The Prediction of Sound Radiation from Real Structures

During product development there is a need for quick, reliable methods to predict noise radiated from real structures such as machinery, appliances, and office products. However, finite element and boundary element analyses require repeated solutions of large models even for small design changes. The efficiency of calculating radiated noise may be improved by starting with models that are optim...

Multilayered Amorphous Silicon Structures

Theory of Nonlinear s-Polarized Phonon-Polaritons in Multilayered Structures

A theory is presented for the dispersion relations of the nonlinear phonon-polaritons arising when phonons are coupled to the electromagnetic waves in multilayered structures of nonlinear materials. The calculations are applied to a multilayered structure consisting of a thin film surrounded by semi-infinite bounding media where each layer may have a frequency dependent dielectric function and ...

Structures in Anisotropic Multilayered Media

Applying the concept of spectral domain representation, the moment method or the point-matching procedure and Green's function theory, a unified approach for the computation of the static capacitance of single, coupled and comb-like metallic structures in anisotropic multilayered media is presented. The media can be electrically shielded on one or both sides. The geometry of the parallel strips...

Sound radiation from nested cylindrical shells

ABSTRACT Fluid-loaded nested cylindrical shells are modelled using a doubled-walled cylindrical shell structure closed at each end by circular end plates and excited by a transverse force at one end. The effects of various influencing factors on the radiated sound power are examined corresponding to non-concentricity of the cylindrical shells, entrained fluid and rib connections in the annular ...