Abstract
Condensed models are used to describe the dynamic behaviour of a multilayer structure by means of an equivalent homogeneous layer defined by intrinsic properties. Existing condensed models mainly describe the bending, membrane and shearing motions of the multilayer plate and neglect its dilatational motion. As a result, the transmission loss across the multilayer may be underestimated if the layers are soft and thick. In this paper, a condensed model of physically symmetric multilayer is developed. The antisymmetric and symmetric motions of the structure are described separately by means of two equivalent admittances. These admittances depend on three intrinsic properties: a dynamic bending stiffness and two dynamic mass densities. The condensed model is validated comparing transmission loss computations with the Transfer Matrix Method for multilayers with elastic or poroelastic cores.
Highlights
Multilayered structures have shown their interest in today’s transportation and construction industries for their performances in term of high stiffness, lightweight or controlled damping that classical materials cannot offer
By analogy with the equivalent symmetric impedance (17), we can increase the accuracy of the condensed model by considering an antisymmetric dynamic mass density ρA in the equivalent impedance: 1 ZA,eq = jω
The coefficients ρA, ρS and Deq correspond to the dynamic intrinsic properties of the proposed condensed model since they do not depend on the angle of incidence of the imposed acoustic wave
Summary
Multilayered structures have shown their interest in today’s transportation and construction industries for their performances in term of high stiffness, lightweight or controlled damping that classical materials cannot offer. All the previous models are generally applied to compute the natural wavenumbers of the structure or the transmission loss (TL) across the multilayer [12] Other methodologies such as condensed models aim to identify an equivalent single layer which describes the behaviour of the multilayer by means of dynamic intrinsic properties. They can be used in finite element software to reduce the time computation substituting multilayer structures with homogeneous layers. The condensed plate models cited previously essentially describes the bending and shearing motions of the multilayer neglecting the dilatational motion since they assume a constant normal displacement. We propose in this paper a condensed model of thick symmetric multilayer considering the bending, shearing and dilatational motions of the structure. TL computations of multilayers with elastic or poroelastic cores are compared to validate the proposed condensed model
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
