Thermo-acoustic analysis of higher-order shear deformable laminated composite sandwich flat panel

2018 ◽  
Vol 22 (5) ◽  
pp. 1357-1385 ◽  
Author(s):  
Nitin Sharma ◽  
Trupti Ranjan Mahapatra ◽  
Subrata Kumar Panda ◽  
Pankaj Katariya
Keyword(s):  
Finite Element ◽  
Acoustic Analysis ◽  
Thermal Environment ◽  
Acoustic Radiation ◽  
Power Level ◽  
Laminated Composite ◽  
Higher Order ◽  
Sandwich Composite ◽  
Composite Sandwich ◽  
Benchmark Solutions

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 elements formulation based on the higher-order shear deformation shell theory. The structural stiffness and mass tensors are obtained using competent finite element steps engaging the Hamilton’s principle followed by computation of acoustic responses by resolving the Helmholtz partial differential equation. An in-house MATLAB code is developed based on the present formulation for the computation of all the desired responses. The accuracy and robustness of the present scheme are recognized by the close conformance of the critical buckling temperature, natural frequencies and the sound power level values with the available benchmark solutions alongside the values obtained via a simulation model implemented using commercially available finite element (ANSYS) and boundary element (LMS Virtual.Lab) packages. Subsequently, the present model is employed to solve wide variety of numerical illustrations and the useful inferences related to the influence of elevated temperature, core-to-face thickness ratio, core-to face modular ratio and lay-up scheme on the sound emission characteristics of sandwich composite flat panels are deliberated in detail.

Numerical analysis of acoustic radiation properties of laminated composite flat panel in thermal environment: A higher-order finite-boundary element approach

2017 ◽  
Vol 232 (18) ◽  
pp. 3235-3249 ◽  
Author(s):  
Nitin Sharma ◽  
Trupti Ranjan Mahapatra ◽  
Subrata Kumar Panda
Keyword(s):  
Boundary Element ◽  
Thermal Loading ◽  
Thermal Environment ◽  
Acoustic Radiation ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Higher Order ◽  
Element Formulation ◽  
Present Scheme ◽  
Acoustic Responses

In this article, the vibration-induced acoustic responses of laminated composite flat panels subjected to harmonic mechanical excitation under uniform temperature load are investigated numerically. The natural frequencies alongside corresponding modes of the flat panels resting on an infinite rigid baffle are obtained by using finite element method in the framework of the higher-order shear deformation theory. A coupled finite and boundary element formulation is then employed to acquire the acoustic responses. The governing equation for the sound radiaiton from the vibrating structures is derived by solving the Helmholtz wave equation. The vibration and acoustic responses are computed by using the present scheme via an in-house computer code developed in MATLAB environment. In order to avoid any excess thermal loading conditions first, the critical buckling temperature of the panel structure is obtained and authenticated with the benchmark values. Further, the sound power levels for isotropic and laminated composite panels are computed using the present scheme and validated with the existing results in the published literature. Finally, the influence of lamination scheme, support conditions and modular ratio on the acoustic radiation behavior of laminated composite flat panels in an elevated thermal environment is studied through various numerical examples. The thermal load is found to have substantial influence on the stiffness of the panels and the peaks in the free vibration responses tend to shift to lower frequencies for higher temperatures. It is also inferred that the panels radiate less efficiently whereas the overall sound pressure level is found to follow an increasing trend with increasing temperature.

scholarly journals Non-linear deflection and stress analysis of laminated composite sandwich plate with elliptical cutout under different transverse loadings in hygro-thermal environment

2020 ◽  
Vol 7 (1) ◽  
pp. 80-100
Author(s):  
Rahul Kumar ◽  
Achchhe Lal ◽  
B. M. Sutaria
Keyword(s):  
Stress Concentration ◽  
Sandwich Plate ◽  
Thermal Environment ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Gauss Point ◽  
Composite Sandwich ◽  
Aspect Ratios ◽  
Present Solution ◽  
Non Linear

AbstractIn this paper, non-linear transverse deflection, stress and stress concentration factors (SCF) of isotropic and laminated composite sandwich plate (LCSP) with and without elliptical cutouts subjected to various trans-verse loadings in hygrothermal environment are studied. The basic formulation is based on secant function-based shear deformation theory (SFSDT) with von-Karman nonlinearity. The governing equation of non-linear deflection is derived using C0 finite element method (FEM) through minimum potential energy approach. Normalized trans-verse maximum deflections (NTMD) along with stress concentration factor is determined by using Newton’s Raphson method through Gauss point stress extrapolation. Influence of fiber orientations, load parameters, fiber volume fractions, plate span to thickness ratios, aspect ratios, thickness of core and face, position of core, boundary conditions, environmental conditions and types of transverse loading in MATLAB R2015a environment are examined. The numerical results using present solution methodology are verified with the results available in the literatures.

scholarly journals The Vibration Response of Composite Sandwich Beam with Delamination

2007 ◽  
Vol 16 (2) ◽  
pp. 096369350701600 ◽  
Author(s):  
Buket Okutan Baba ◽  
Ronald F. Gibson
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Sandwich Beam ◽  
Laminated Composite ◽  
Sandwich Beams ◽  
Element Analysis ◽  
Composite Sandwich ◽  
Dimensional Finite Element ◽  
Vibration Tests ◽  
Non Destructive

The aim of this study is to report the effect of delamination on the vibration characteristics of composite sandwich beams. The natural frequencies and corresponding vibration modes of a free-free sandwich beam with delamination of various sizes and locations are predicted using a two-dimensional finite element analysis (FEA). The presence of delamination affects the stiffness of the delaminated beam and results in differences on the natural frequencies of the beam. Assessment of the differences light the way for the existence, size and location of the delaminated region and can be used for a non-destructive evaluation of the damage characteristics of the delaminated beams. Vibration tests are conducted on fully bonded sandwich beams with carbon/epoxy laminated composite faces and foam core to verify the finite element results. Agreement between predictions of the model and experimental observations is good.

Nonlinear finite element analysis of smart laminated composite sandwich plates

2014 ◽  
Vol 14 (03) ◽  
pp. 1350075 ◽  
Author(s):  
S. K. Sarangi ◽  
B. Basa
Keyword(s):  
Finite Element ◽  
Fiber Composite ◽  
Orientation Angle ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Numerical Results ◽  
Sandwich Plates ◽  
Fe Model ◽  
Composite Sandwich ◽  
Composite Sandwich Plates

This paper deals with the nonlinear dynamic analysis of smart laminated composite sandwich plates. A three dimensional energy based finite element (FE) model has been developed for the composite sandwich plates integrated with the patches of active constrained layer damping (ACLD) treatment. Von Kármán type nonlinear strain–displacement relations and the first-order shear deformation theory (FSDT) are adopted individually for each layer of the sandwich plate in developing the FE model. The constraining layer of the ACLD treatment is considered to be made of active fiber composite (AFC) material. The Golla–Hughes–McTavish (GHM) method is used to model the constrained viscoelastic layer of the ACLD treatment in the time domain. Sandwich plates with symmetric and antisymmetric laminated faces separated by HEREX core are considered for evaluation of the numerical results. The numerical results indicate that the ACLD patches significantly improve the damping characteristics of the composite sandwich plates for suppressing their geometrically nonlinear transient vibrations. The effect of variation of piezoelectric fiber orientation angle in the AFC material on the control authority of the ACLD patches is also investigated.

Thermomechanical Buckling of Laminated Composite Plates Using Mixed, Higher-Order Analytical Formulation

2002 ◽  
Vol 69 (6) ◽  
pp. 790-799 ◽  
Author(s):  
J. B. Dafedar ◽  
Y. M. Desai
Keyword(s):  
Strain Tensor ◽  
Single Layer ◽  
Laminated Composite ◽  
Composite Plates ◽  
Higher Order ◽  
Laminated Composite Plates ◽  
Individual Layer ◽  
Energy Principle ◽  
Transverse Stresses ◽  
Benchmark Solutions

A novel, analytical mixed theory based on the potential energy principle has been presented in this paper to investigate buckling response of laminated composite plates subjected to mechanical and hygrothermal loads. Two sets of higher-order mixed models have been proposed on the basis of an individual layer as well as equivalent single layer theories by selectively incorporating nonlinear components of Green’s strain tensor. Displacements, as well as transverse stress continuities, have been enforced in the formulation of models by incorporating displacements and transverse stresses as the degrees-of-freedom. The modal transverse stresses have been obtained as eigenvectors and thus their separate calculations have been advantageously avoided. Solutions from the models have been shown to be in excellent agreement with the available three-dimensional elasticity solutions. Few benchmark solutions have also been presented for the bi-axial compression-tension loading.

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