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.

Chandramouli Padmanabhan

Department of Mechanical Engineering

Natrajan Ganesan

Anisotropy

Boundary conditions

Composite structures

finite element method

Flow of fluids

Fluid structure interaction

Shear deformation

Stiffness

Structural analysis

Vibrations (mechanical)

Viscoelasticity

Wave equations

BERNOULLI'S EQUATIONS

COMPOSITE SHELLS CONVEYING FLUIDS

COUPLED FORMULATION

Dynamic pressure

Shells (structures)

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Journal of Sound and Vibration

A formulation, based on the semi-analytical finite element method, is proposed for elastic conical shells conveying fluids. The structural equations are based on the shell element proposed by Ramasamy and Ganesan [Finite element analysis of fluid-filled isotropic cylindrical shells with constrained viscoelastic damping, Computers & Structures 70 (1998) 363-376] while the fluid model is based on velocity potential formulation used by Jayaraj et al. [A semi-analytical coupled finite element formulation for composite shells conveying fluids, Journal of Sound and Vibration 258(2) (2002) 287-307]. Dynamic pressure acting on the walls is derived from Bernoulli's equation. By imposing the requirement that the normal component of velocity of the solid and fluid are equal leads to fluid-structure coupling. The computer code developed has been validated using results available in the literature for cylindrical shells conveying fluid. The study has been carried out for conical shells of different cone angles and for boundary condition like clamped-clamped, simply supported and clamped free. In general, instability occurs at a critical fluid velocity corresponding to the shell circumferential mode with the lowest natural frequency. Critical fluid velocities are lower than that of equivalent cylindrical shells. This result holds good for all boundary conditions. © 2007 Elsevier Ltd. All rights reserved.

Dynamic analysis of conical shells conveying fluid

The flow of hot fluid having a harmonic component superposed on the mean flow velocity is considered flowing through an insulated cylindrical shell. The cylindrical shell will be subjected to thermal load due to the flow of hot fluid. The semi-analytical finite element forms the basis for modelling the structural continuum under the influence of temperature and the flowing fluid. The fluid flowing through the cylindrical shell is incompressible and linear potential flow theory is used to formulate the fluid domain. Bernoulli's principle and impermeability conditions of the fluid are the basis for a coupled fluid-structure interaction analysis. Model reduction technique in conjunction with the fourth order Runge-Kutta method using Gill's coefficient is adopted to compute the state transition matrix which provides the stability information of the periodic system. The results of the theoretical studies are presented related to instability regions due to a pulsatile flow of hot fluid through a cylindrical shell. Hot fluid at various magnitude of constant temperature limited by the critical thermal buckling temperature is considered in the study. The effect of fluid temperature and excitation parameter on the behavior of dynamic instability of the system is examined. © 2003 Elsevier Ltd. All rights reserved.

A study on the dynamic stability of a cylindrical shell conveying a pulsatile flow of hot fluid

Vast literature is available for modeling the coupled fluid structure interaction involving the flow of a pulsatile fluid through pipes/shells under ambient temperature. In contrast it is found that there is no literature on such problems under the influence of temperature. This paper considers the evaluation of dynamic instability regions due to a flow of pulsating hot fluid through an insulated composite cylindrical shell. A coupled fluid structure interaction model in conjunction with uncoupled thermomechanical model is used for analysis. The system's equations of motion containing periodic coefficients are expressed in modal domain considering linear transformation. Fourth order Runge-Kutta method using Gill's coefficient is adopted to compute the state transition matrix which provides the stability information of the periodic system following the Floquet-Liapunov theory. Pulsatile flow of water at various magnitude of steady state temperature is considered and hence the effect of water temperature on the instability regions is analyzed. The influence of lamina fibre angle on the instability regions is also examined. © 2004 Elsevier Ltd. All rights reserved.

Composite Structures

Parametric resonance of a composite cylindrical shell containing pulsatile flow of hot fluid

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.

Computers and Structures

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

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.

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

Journal of Fluids and Structures

APPLICATION OF A GENERAL PURPOSE FINITE ELEMENT METHOD TO ELASTIC PIPES CONVEYING FLUID

VIBRATION ANALYSIS OF ANISOTROPIC OPEN CYLINDRICAL SHELLS SUBJECTED TO A FLOWING FLUID

Computers & Structures

Natural frequencies and critical velocities of fixed-fixed laminated circular cylindrical shells conveying fluids

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

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