Finite element computation of the vibrations of a plate-fluid system with interface damping (original) (raw)
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Modelling and numerical solution of elastoacoustic vibrations with interface damping
International Journal for Numerical Methods in Engineering, 1999
A finite element method is applied to compute the vibrations of an elastoacoustic system subject to an external harmonic excitation. The effect of a thin layer of noise damping material between the fluid and the solid is taken into account by relaxing the interface kinematic condition of perfect contact. We consider the non-linear eigenvalue problem arising from the free vibration problem for the damped system. For the case of a fluid in a rectangular rigid cavity with one absorbing wall, we deduce the dispersion equation which allows computing analytically its eigenvalues and eigenmodes and compare the numerical solution with them. Finally, we apply the finite element method to assess the effect of introducing a real viscoelastic material to damp the elastoacoustic vibrations of a coupled system.
Acoustic Structure Interaction with Damping Interface
This paper deals with the finite element method to compute the vibrations of a fluid-structure coupled system. The fluid structure system consists of an acoustic fluid and a plate structure. The Finite element analysis is done with and without the interphase damping and the results are compared. The damping material separates both the media, the fluid and the structure. The plate structure is described by a displacement field which contains an inviscid, compressible and barotropic fluid. The barotropic fluid is described by a pressure field. The gravity effects are neglected in the study. The aim of this study is to develop new noise reduction techniques in fluid structure interaction. The originality of the work lies in introducing a damping interphase in fluid structure interaction using ANSYS software and also intends to develop a simulated experiment of impedance tube.
Numerical computation of elastoacoustic vibrations with interface damping
In this paper we introduce and analize a finite element method to compute the vibrations of a coupled fluid-solid system subjected to an external harmonic excitation. The effect of a thin layer of noise damping material between the fluid and the solid is taken into account by relaxing the interface kinematic condition of perfect contact. A complete analysis is included: the continuous problem is shown to be well posed and optimal error estimates are proved for the numerical method. Numerical results showing the response of the system with respect to the excitation frequency are presented.
Numerical vibroacoustic analysis of plates with constrained-layer damping patches
The Journal of the Acoustical Society of America, 2011
A numerical vibroacoustic model that can manage multilayered plates locally covered with damping patches is presented. All the layers can have an on-axis orthotropic viscoelastic behavior. Continuity of displacements and transverse shear stresses at each interface is enforced, that permits to write the entire displacement field in function of the displacements of the -common-first layer, leading to a two-dimensional plate model. The problem is then discretized by Rayleigh-Ritz's method using a trigonometric basis that includes both sine and cosine functions in order to treat various boundary conditions. The excitation can be of mechanical kind (concentrated or distributed forces) or of acoustic kind (plane wave of any incidence, diffuse field, etc.). The model permits to compute different vibroacoustic indicators: the mean square velocity of the plate, the radiation efficiency and the transmission loss. Comparisons between the present model and numerical results from literature or finite element computations show that the model gives good results in both mechanical and acoustical aspects. Then, a comparison of the effects of different distributions of patches is presented. The role of the surface covering rate is first discussed, followed by a study involving different geometries for the same surface covering rate.
Vibration analysis of rectangular plates coupled with fluid
Applied Mathematical Modelling, 2008
The approach developed in this paper applies to vibration analysis of rectangular plates coupled with fluid. This case is representative of certain key components of complex structures used in industries such as aerospace, nuclear and naval. The plates can be totally submerged in fluid or floating on its free surface. The mathematical model for the structure is developed using a combination of the finite element method and Sanders' shell theory. The in-plane and out-of-plane displacement components are modelled using bilinear polynomials and exponential functions, respectively. The mass and stiffness matrices are then determined by exact analytical integration. The velocity potential and Bernoulli's equation are adopted to express the fluid pressure acting on the structure. The product of the pressure expression and the developed structural shape function is integrated over the structure-fluid interface to assess the virtual added mass due to the fluid. Variation of fluid level is considered in the calculation of the natural frequencies. The results are in close agreement with both experimental results and theoretical results using other analytical approaches.
2007
This work deals with a coupled acoustic problem: a fluid contained in a rigid cavity except on its top, where a flexible plate is placed. We present a numerical method to compute the solution of this problem when a monopole harmonic excitation is applied on the bottom of the fluid. The last aim of our work is the minimization of the sound radiated by the plate to the exterior that will be developed in future works. We model the problem using the pressure to characterize the fluid equations meanwhile for the plate the Reissner-Mindlin model is used. A complex elasticity modulus has been considered for the plate, according to the ASTM754-04 standard. This coupled problem is solved numerically with a finite element method based on Lagrange hexahedral elements in the fluid and MITC4 elements in the plate. This numerical method is free of shear locking. In order to improve the precision of the method, a discretization with nonmatchig meshes has been applied and, to avoid the Dirac-Delta ...
A displacement method for the analysis of vibrations of coupled fluid-structure systems
International Journal for Numerical Methods in Engineering, 1978
A variational principle in terms of displacements in the fluid and the structure with a penalty for irrotationality of displacement in the fluid is developed for the analysis of harmonic vibrations of ideal compressible fluid and elastic structure systems. Its Discretization by the finite element method leads to an algebraic eigenvalue problem with a positive definite symmetric banded matrix. Numerical examples obtained for pure acoustic cases and coupled cases show the efficiency of the method.
IJERT-Acoustic Structure Interaction with Damping Interface
International Journal of Engineering Research and Technology (IJERT), 2016
https://www.ijert.org/acoustic-structure-interaction-with-damping-interface https://www.ijert.org/research/acoustic-structure-interaction-with-damping-interface-IJERTV4IS110289.pdf This paper deals with the finite element method to compute the vibrations of a fluid-structure coupled system. The fluid structure system consists of an acoustic fluid and a plate structure. The Finite element analysis is done with and without the interphase damping and the results are compared. The damping material separates both the media, the fluid and the structure. The plate structure is described by a displacement field which contains an inviscid, compressible and barotropic fluid. The barotropic fluid is described by a pressure field. The gravity effects are neglected in the study. The aim of this study is to develop new noise reduction techniques in fluid structure interaction. The originality of the work lies in introducing a damping interphase in fluid structure interaction using ANSYS software and also intends to develop a simulated experiment of impedance tube.
Finite element modeling of vibration and sound radiation from fluid-loaded damped shells
Thin-walled Structures, 2000
The vibration and noise radiation from fluid-loaded cylindrical shells are controlled by using multiple stiffeners and passive constrained layer damping treatment. Dynamic and fluid finite elements are developed to study the fundamental phenomena governing the coupling between the stiffened shell, with and without damping, and the fluid domain surrounding it. The models are used to predict the response of the shell and to evaluate the effect of stiffening rings and damping treatment on both the structural vibration and noise radiation in the fluid domain. The geometry of the shell and fluid domain allows the formulation of a harmonic-based model, which uncouples the fluid-structural response of modes corresponding to different numbers of circumferential nodes.