The natural frequencies and loss factors in cylindrical shells with a constrained viscoelastic layer between two isotropic, elastic facings are studied using the finite element method. The finite element is developed based on a discrete layer theory assuming variation of inplane displacements across the thickness and a constant transverse displacement. Effects of the boundary conditions, shear parameter and ratio of core to facing thickness on the natural frequencies and loss factors of cylindrical shells are presented. © 1993.

T. C. Ramesh

Natrajan Ganesan

Damping

ELASTICITY

finite element method

Vibrations (mechanical)

Viscoelasticity

CONSTRAINED DAMPING LAYER

Cylindrical Shells

DISCRETE LAYER THEORY

INPLANE DISPLACEMENTS

Structural analysis

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IIT Madras

Vibration and damping analysis of cylindrical shells with a constrained damping layer

Computers and Structures

A coupled formulation based on the semi-analytical finite element technique is developed for composite shells conveying fluid. The structural finite element formulation is from Ramasamy and Ganesan (1998 Computers and Structures 70, 363-376), while the fluid part is modelled by the characteristic wave equation. The fluid part is modelled using a velocity potential formulation and the dynamic pressure acting on the walls is derived from Bernoulli's equation. Impermeability and dynamic condition are imposed on the fluidstructure interface. The finite element equations for the composite shell conveying fluid are validated using available results in the literature. A detailed parametric study is carried out for various boundary conditions as well as for different length-to-radius and radius-to-thickness ratios. © 2002 Elsevier Science Ltd. All rights reserved.

Journal of Sound and Vibration

A semi-analytical coupled finite element formulation for composite shells conveying fluids

Active constrained layer damping in cylindrical shells of revolution are studied. A three noded, isoparametric, multilayered, semianalytical finite element is developed and used. A layerwise theory is assumed for the thickness variation of the displacements and electric potential. The electrodes on the sensors/actuators are spatially shaped to reduce spillover between circumferential modes. The effect of axial and circumferential mode numbers, feedback factor, length to radius ratio, radius to thickness ratio of the shell, percentage area of the shell covered with collocated piezoelectric sensors/actuators and the axial location of the collocated sensors/actuators, on the damping ratio of the cylindrical shells of revolution are studied. A comparison is also made between the active constrained layer damping and the conventional passive constrained layer damping treatments for the class of shells considered. © 2001 Elsevier Science Ltd.

Semianalytical finite element analysis of active constrained layer damping in cylindrical shells of revolution

The modal strain energy method is used to study the energy dissipation pattern in vibrating cylindrical shells with a viscoelastic damping layer, for various circumferential and axial modes. The effect of tank size, boundary condition and height of contained fluid on the distribution pattern is also investigated. The regions of energy dissipation concentration are identified. The effect of redistribution of the (initially uniformly distributed) constrained viscoelastic material by concentrating it in the above regions is studied.

Study on energy dissipation pattern in vibrating fluid filled cylindrical shells with a constrained viscoelastic layer

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.

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

A refined dynamic theory for viscoelastic cylindrical shells and cylindrical laminated composites, Part 1: General theory

AIAA Journal

Vibration and Damping Analysis of a Multilayered Cylindrical Shell, Part 11: Numerical Results

Vibration and damping analysis of a multilayered cylindrical shell. I - Theoretical analysis

The Shock and Vibration Digest

Vibration Control With Viscoelastic Materials - III

Journal of Engineering for Industry

The Effect of Structural Damping on the Forced Vibrations of Cylindrical Sandwich Shells

Journal	Computers and Structures
ISSN	00457949
Open Access	No