In this article, buckling and vibration behavior of a functionally graded material (FGM) sandwich beam having constrained viscoelastic layer (VEL) is studied in thermal environment by using finite element formulation. The FGM sandwich beam is assumed to be clamped on both edges. The material properties of FGM are functionally graded in thickness direction according to volume fraction power law distribution. Temperature dependent material properties of FGM stiff layer and shear modulus of viscoelastic layer are considered to carry out buckling and vibration analysis. Numerical studies involving the understanding the effect of power law index, core to stiff layer ratio on the thermal buckling temperature as well as on vibration has been carried out. In addition influence of temperature on natural frequencies and loss factors have been examined for FGM sandwich beam. © 2006 Elsevier Ltd. All rights reserved.

Rajesh K. Bhangale

Natrajan Ganesan

finite element method

Functionally graded materials

Natural frequencies

Numerical methods

Particle beams

Sandwich structures

Thermoelasticity

Vibration control

Viscoelasticity

Volume fraction

CONSTRAINED VISCOELASTIC CORE

Power law index

Sandwich beam

VIBRATION BEHAVIOR

Buckling

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IIT Madras

Journal of Sound and Vibration

In this paper, the vibration and damping of a hollow sandwich box column containing a viscoelastic layer (VEL) or an electrorheological (ER) or magnetorheological (MR) fluid core with a constraining layer are analyzed and a comparison of performance is made. The hollow sandwich box column comprises two skin plates and a VEL/ER/MR fluid core layer. The finite element method is used to study the vibration and damping behaviors of the column. The natural frequencies and modal loss factors are obtained by solving the complex eigenvalue problem. The modal dampings and natural frequencies of the column are calculated for various electric as well as magnetic fields and their performance is compared with that of the viscoelastic core layer for the clamped-free boundary condition. Effects of core thickness, electric voltage and magnetic field on the vibration behavior of the sandwich box column are investigated. © 2008 World Scientific Publishing Company.

International Journal of Structural Stability and Dynamics

Vibration and damping studies on a hollow sandwich box column with a viscoelastic/electrorheological/magnetorheological fluid core layer by the finite element method

The paper deals with the investigation of linear buckling and free vibration behavior of layered and multiphase magneto-electro-elastic (MEE) beam under thermal environment. The constitutive equations of magneto-electro-elastic materials are used to derive finite element equations involving the coupling between mechanical, electrical and magnetic fields. The finite element model has been verified with the commercial finite element package ANSYS. The influence of magneto electric coupling on critical buckling temperature is investigated between layered and multiphase magneto-electro-elastic beam. Furthermore, the influence of temperature rise on natural frequencies of magneto-electro-elastic beam with layered and different volume fraction is presented. © 2007 VSP.

Multidiscipline Modeling in Materials and Structures

Buckling and vibration analysis of layered and multiphase magneto-electro-elastic beam under thermal environment

Thermoelastic buckling and vibration behavior of a functionally graded sandwich beam with constrained viscoelastic core

In recent years, structures made up of functionally graded materials (FGMs) have received considerable attention for use in high-temperature applications. In this article, a finite element formulation based on First-Order Shear Deformation Theory (FSDT) is used to study the thermal buckling and vibration behavior of truncated FGM conical shells in a high-temperature environment. A Fourier series expansion for the displacement variable in the circumferential direction is used to model the FGM conical shell. The material properties of the truncated FGM conical shells are functionally graded in the thickness direction according to a volume fraction power law distribution. Temperature-dependent material properties are considered to carry out a linear thermal buckling and free vibration analysis. The conical shell is assumed to be clamped-clamped and has a high temperature specified on the inner surface while the outer surface is at ambient temperature. The one-dimensional heat conduction equation is used across the thickness of the conical shell to determine the temperature distribution and thereby the material properties. In addition, the influence of initial stresses on the frequency behavior of FGM shells has also been investigated. Numerical studies involving the understanding of the role of power law index, r/h ratios, and semi-vertex angle on the thermal buckling temperature as well as on vibration have been carried out. © 2005 Elsevier Ltd. All rights reserved.

Linear thermoelastic buckling and free vibration behavior of functionally graded truncated conical shells

A semianalytical finite element for doubly curved, multilayered shells of revolution, based on an extension of the displacement field proposed by Wilkins et al., is proposed. Numerical analysis is done to study the vibration and damping characteristics of multilayered fluid filled shells with alternating elastic and viscoelastic layers. The effect of varying the number of viscoelastic layers on the vibration and damping characteristics is also studied. The effect of the fluid is incorporated by the added mass concept. The effect of shear parameter on natural frequency and modal loss factor is studied for various circumferential and axial modes.

Computers and Structures

Vibration and damping analysis of multilayered fluid filled cylindrical shells with constrained viscoelastic damping using modal strain energy method

The finite element code is developed based on the displacement field proposed by Wilkins et al. to find out the natural frequencies and loss factors of fluid filled cylindrical shells with a constrained viscoelastic layer in between two facings made of composite material. The fluid effect on the natural frequencies and loss factors are taken care of by the added mass of the fluid on the structure. Effects of the fluid height, ratio of core to facing thickness and facing fibre orientation on the natural frequencies and loss factors of cylindrical shells are presented.

Vibration and damping analysis of fluid filled orthotropic cylindrical shells with constrained viscoelastic damping

The free vibration and damping characteristics of three-layered conical shells with a viscoelastic core constrained by isotropic facings are studied using the finite element method. Results are presented for shells with various geometric and physical parameters. Three boundary conditions are considered in the analysis: clamped-clamped, simply supported and clamped at the small end and free at the other. © 1994 Academic Press Limited.

Journal	Journal of Sound and Vibration
Publisher	Academic Press
ISSN	0022460X
Open Access	No