Vibro-acoustic energy propagation in anisotropic, anelastic porous materials

• Historically, the modelling of the acoustics of poro-elastic materials (APEMs) has assumed the materials to be isotropic in both their elastic as well as their acoustic properties including the dissipative mechanisms related to viscous, inertialand thermal interactions. While this is a reasonable approximation when the absorption of sound is of interest, it fails to provide meaningful results for most foamed materials in general and for certain sets of boundary conditions involving elastic contact with solids or other APEMs in particular. A general modelling of fully anisotropic APEMs will be reviewed and taken as a starting point for a series of numerical experiments focussing on aspects of propagation of vibro-acoustic energy, in a homogeneous layer as well as in multiple layer arrangements. From previous works it is known that the influence of anisotropy may be quite significant, in particular for structure-borne vibro-acoustic energy. In addition, it is known that the alignment of principal directions may have substantial influence on the transmission of vibro-acoustic energy. These findings will be recalled in order to prepare for a discussion on the aspects of the directional dependence of the anelastic moduli which will be the core of the presentation at the conference. Real material tensors may be constructed from a superposition of these anisotropic contributions, in the most general case, not necessarily sharing the same principal directions. Starting from these fully anisotropic constitutive tensors with general symmetry properties, studies of optimal alignment between conservative and dissipative tensors, as well as between different materials in various configurations of interest, will be illustrated in the lecture.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)

Nyckelord

Anisotropic

Anelastic

Poro-elastic materials

Acoustics

Vibrations

Engineering Mechanics

Teknisk mekanik

Publikations- och innehållstyp

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