Stress convergence in adaptive resolution of boundary layers in the case of 3D-based firstand higher-order shell models

2016 ◽  
pp. 397-400
Author(s):  
Ł Miazio ◽  
G Zboiński
Keyword(s):  
Boundary Layers ◽  
Higher Order ◽  
Adaptive Resolution ◽  
Shell Models

Analytical higher-order-theories for noise reduction analysis of viscoelastic composite multilayered shells

2021 ◽  
pp. 095440622098233
Author(s):  
A Alaimo ◽  
C Orlando ◽  
S Valvano
Keyword(s):  
Sound Transmission ◽  
Higher Order ◽  
Sound Insulation ◽  
Viscoelastic Layer ◽  
Multilayered Structures ◽  
Viscoelastic Composite ◽  
Damping Behavior ◽  
Shell Models ◽  
Composite Layers ◽  
Insulation Effect

The noise transmission of aeronautical panels is an important phase of the design process of an airplane. In this work an analytical Navier-type solution, based on higher-order layer-wise shell models, is proposed for the analysis of the sound insulation of laminated panels. The considered multilayered structures are laminated with cross-ply composite layers embedded with interlaminar viscoelastic sheets. The use of the soft interlayers permits to have a passive insulation effect in the study of the sound transmission. In order to take into account the frequency depedent properties of a realistic viscoelastic layer, the damping behavior is modeled through a fractional derivative Zener model. The Rayleigh integral method is used to extrapolate the acoustic indicators for the sound transmission analysis. Some results are presented to validate the efficiency of the present approach, comparing the present solutions with others taken from the literature.

scholarly journals Lattice Dynamics of Simple Harmonic and Anharmonic Shell Models

1967 ◽  
Vol 20 (5) ◽  
pp. 495 ◽  
Author(s):  
J Oitmaa
Keyword(s):  
Dipole Moment ◽  
Shell Model ◽  
Lattice Dynamics ◽  
Higher Order ◽  
Force Constants ◽  
Dynamical Equations ◽  
Normal Coordinates ◽  
Shell Models ◽  
Rigid Ion Model ◽  
Explicit Expressions

The lattice dynamics of harmonic and anharmonic shell models are reviewed. It is shown that the various dynamical equations for the shell model can be expressed in the same form as those for the rigid ion model, but with modified force constants. The anharmonic shell model leads to higher order contributions to the dipole moment, quadratic and cubic in the normal coordinates, for which explicit expressions are obtained.

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