Vibro-acoustic behavior of a multilayered viscoelastic sandwich plate under a thermal environment:
12 Jul 2011-Journal of Sandwich Structures and Materials (SAGE Publications)-Vol. 13, Iss: 5, pp 509-537
TL;DR: In this paper, the authors present numerical simulation studies on the vibration and acoustic response characteristics of a multilayered viscoelastic sandwich plate in a thermal environment, where the critical buckling temperature and vibration response were obtained using finite element method while sound radiation characteristics are obtained using boundary element method.
Abstract: This article presents numerical simulation studies on the vibration and acoustic response characteristics of a multilayered viscoelastic sandwich plate in a thermal environment. Initially the critical buckling temperature is obtained followed by free and forced vibration analyses considering the pre-stress due to the imposed thermal environment in the plate. The vibration response predicted is then used to compute the sound radiation. The critical buckling temperature and vibration response are obtained using finite element method while sound radiation characteristics are obtained using boundary element method. It is found that resonant amplitude of both the vibration and acoustic response decreases with increase in temperature. The influence of core thickness, number of layers, type of thermal field, and type of viscoelastic core material on vibration response sound radiation characteristics are studied in detail.
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TL;DR: In this article, the acoustic radiation responses of laminated sandwich baffled flat panels subjected to harmonic loading in an elevated thermal environment were investigated via a novel coupled finite and boundary boundary model.
Abstract: The acoustic radiation responses of laminated sandwich baffled flat panels subjected to harmonic loading in an elevated thermal environment are investigated via a novel coupled finite and boundary ...
19 citations
Cites methods from "Vibro-acoustic behavior of a multil..."
...Further, coupled FEM– BEM scheme implemented via commercial software have been utilized to study the acoustic radiation emanating from sandwich flat [30] and sandwich composite cylindrical shell panels with viscoelastic core [31] in thermal environment....
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TL;DR: In this article, a study of vibroacoustic behavior of sandwich shell panels with laminated composite faces under concentrated harmonic loading in a hygrothermal environment by means of a higher-order finite-boundary element model is presented.
16 citations
TL;DR: In this article, a theoretical and experimental investigation of composite plate comprising fiber-reinforced polymer (FRP) laminates with a porous foam core (PFC) subjected to planar acoustic wave (PAW) excitation is performed.
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TL;DR: In this paper, the displacement fields of the plate and stiffeners are formulated on the basis of the first-order shear deformation theory and the theoretical sound pressure level (SPL) curve is constructed using the responses at different excitation frequencies and the first Rayleigh integral.
15 citations
TL;DR: In this paper, a coupled finite-boundary elements formulation based on the higher-order shear deformation shell theory has been proposed and implemented via a domestic MATLAB code for the computation of the responses.
Abstract: The present paper deals with the vibration induced acoustic responses of baffled sandwich curved shell panels constituted of laminated composite face sheets and subjected to harmonic point excitation in an elevated thermal environment by an effective computational approach. A coupled finite-boundary elements formulation based on the higher-order shear deformation shell theory has been proposed and implemented via a domestic MATLAB code for the computation of the responses. The eigen frequencies in conjunction with the conforming modes of the vibrating thermally pre-stressed composite sandwich panel are obtained using competent finite element steps engaging the Hamilton’s principle. The critical buckling temperature of the sandwich panel structure is assessed to prevent any excess thermal loading during analysis followed by the computation of acoustic responses by solving the Helmholtz wave equation using the boundary element steps. The performance and the versatility of the present scheme is established by the convergence study and the successive comparison of the present numerical responses, for instance the critical buckling temperature and the radiated sound power, with the available benchmark solutions. The sound power emitted by thermally stressed composite sandwich panel is also computed via simulation model developed using commercial software ANSYS and LMS Virtual.Lab and compared with the present values. Numerous numerical examples are solved to deeply discuss the influence of various design parameters on the vibroacoustic responses of laminated composite sandwich curved panels under high temperature environment.
12 citations
References
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30 Jun 1999
TL;DR: The Inverse Problem: Cylindrical NAH. as discussed by the authors The Inverse problem: Planar NAH and the Inverse NP-hardness of planar plane waves.
Abstract: Preface. Fourier Transforms & Special Functions. Plane Waves. The Inverse Problem: Planar NAH. Cylindrical Waves. The Inverse Problem: Cylindrical NAH. Spherical Waves. Spherical NAH. Green Functions & the Helmholtz Integral. Index.
1,032 citations
"Vibro-acoustic behavior of a multil..." refers background or methods in this paper
...To understand why the concept of replacing the actual velocity distribution with a spatially averaged uniform rms velocity works, the alternative expression for sound power (using Rayleigh’s Integral) as shown by Williams [18] is considered: ! ð Þ 1⁄4 0ck 2 4 Z Z...
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...To understand why the concept of replacing the actual velocity distribution with a spatially averaged uniform rms velocity works, the alternative expression for sound power (using Rayleigh’s Integral) as shown by Williams [18] is considered: !ð Þ ¼ 0ck 2 4 Z Z S Z Z S _U x0, y0ð Þ sin kRð Þ kR U x, yð Þdsds0 ð34Þ In the above equation R ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi x x0ð Þ2þ y y0ð Þ2 q where x yð Þ and x0 y0ð Þ are co-ordinates of two different point on the plate, S or S’ represents the plate area, _U is the normal velocity of the plate (assumed to be harmonic), and _U is its complex conjugate....
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...Temperature-dependant material properties of visco-elastic core materials EC2216 and DYAD 606 [18]: (a) shear modulus, (b) material loss factor....
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TL;DR: In this article, an efficient method for finite element modeling of three-layer laminates containing a viscoelastic layer is described, and modal damping ratios are estimated from undamped normal mode results by means of the modal strain energy method.
Abstract: An efficient method is described for finite element modelling of three-layer laminates containing a viscoelastic layer. Modal damping ratios are estimated from undamped normal mode results by means of the modal strain energy method. Comparisons are given between results obtained by the MSE method implemented in NASTRAN, by various exact solutions for approximate governing differential equations, and by experiment. Results are in terms of frequencies, modal damping ratios, and mechanical admittances for simple beams, plates, and rings. Application of the finite element -- MSE method in design of integrally damped structures is discussed.
542 citations
"Vibro-acoustic behavior of a multil..." refers methods in this paper
...Johnson and Kienholz [2] described finite element based modal strain energy method to obtain modal damping ratios....
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TL;DR: In this article, the authors present a time-stepping method for convective heat transfer with phase change problems and linear Steady State Problems, and a non-linear heat-conduction analysis.
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329 citations
TL;DR: In this article, the authors re-examined the definition of loss factor in terms of energy quantities, particularly as it applies to composite viscoelastic systems, and proposed simple relations which express the loss factors of series-parallel arrays of massless VRSs.
Abstract: The definition of loss factor in terms of energy quantities is re‐examined, particularly as it applies to composite viscoelastic systems. A restatement of this definition in terms of a corresponding viscoelastic spring is used to show that this definition is extremely useful for massless (ideal viscoelastic spring) systems, but may be applied unambiguously to spring systems with a single attached mass only at resonance. Simple relations are presented which express the loss factors of series‐parallel arrays of massless viscoelastic springs in terms of properties of the individual components. Implications of these relations in damping of composite structures are discussed. (This work was supported in part by the Aeronautical Systems Division, U. S. Air Force.)
319 citations
"Vibro-acoustic behavior of a multil..." refers background in this paper
...Ungar and Kerwin [1] were the earlier researchers who found that the modal loss factor can be obtained by calculating the ratio of the dissipating energy to the total structural energy, using modal strain energy method....
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