Aerothermoelastic Stability of Functionally Graded Circular Cylindrical Shells

2010 ◽  
Author(s):  
Farhad Sabri ◽  
Aouni A. Lakis
Keyword(s):  
Finite Element ◽  
Power Law ◽  
Shell Thickness ◽  
Circular Cylindrical Shell ◽  
Cylindrical Shells ◽  
Functionally Graded ◽  
Element Formulation ◽  
Power Law Distribution ◽  
Aerodynamic Pressure ◽  
Circular Cylindrical Shells

In this work, a hybrid finite element formulation is presented to predict the flutter boundaries of circular cylindrical shells made of functionally graded materials. The development is based on the combination of linear Sanders thin shell theory and classic finite element method. Material properties are temperature dependent, and graded in the shell thickness direction according to a simple power law distribution in terms of volume fractions of constituents. The temperature field is assumed to be uniform over the shell surface and along the shell thickness. First order piston theory is applied to account for supersonic aerodynamic pressure. The effects of temperature rise and shell internal pressure on the flutter boundaries of FG circular cylindrical shell for different values of power law index are investigated. The present study shows efficient and reliable results that can be applied to the aeroelastic design and analysis of shells of revolution in aerospace vehicles.

Efficient Hybrid Finite Element Method for Flutter Prediction of Functionally Graded Cylindrical Shells

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Farhad Sabri ◽  
Aouni A. Lakis
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Power Law ◽  
Shell Thickness ◽  
Cylindrical Shells ◽  
Functionally Graded ◽  
Element Formulation ◽  
Aerodynamic Pressure ◽  
Hybrid Finite Element ◽  
Element Method

In this work, a hybrid finite element formulation is presented to predict the flutter boundaries of circular cylindrical shells made of functionally graded (FG) materials. The development is based on a combination of linear Sanders thin shell theory and the classic finite element method. Material properties are temperature dependent and graded in the shell thickness direction according to a simple power law distribution in terms of volume fractions of constituents. The temperature field is assumed to be uniform over the shell surface and along the shell thickness. First-order piston theory is applied to account for supersonic aerodynamic pressure. The effects of temperature rise and shell internal pressure on the flutter boundaries of a FG circular cylindrical shell for different values of power law index are investigated. The present study shows efficient and reliable results that can be applied to aeroelastic design and analysis of shells of revolution in aerospace vehicles.

scholarly journals Vibration Characteristics of Ring-Stiffened Functionally Graded Circular Cylindrical Shells

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Muhmmad Nawaz Naeem ◽  
Shazia Kanwal ◽  
Abdul Ghafar Shah ◽  
Shahid Hussain Arshad ◽  
Tahir Mahmood
Keyword(s):  
Circular Cylindrical Shell ◽  
Cylindrical Shells ◽  
Vibration Characteristics ◽  
Functionally Graded ◽  
Lagrangian Function ◽  
Dynamical Equations ◽  
Graded Materials ◽  
Present Technique ◽  
Circular Cylindrical Shells ◽  
Stiffened Cylindrical Shells

The vibration characteristics of ring stiffened cylindrical shells are analyzed. These shells are assumed to be structured from functionally graded materials (FGM) and are stiffened with isotropic rings. The problem is formulated by coupling the expressions for strain and kinetic energies of a circular cylindrical shell with those for rings. The Lagrangian function is framed by taking difference of strain and kinetic energies. The Rayleigh-Ritz approach is employed to obtain shell dynamical equations. The axial model dependence is approximated by characteristic beam functions that satisfy the boundary conditions. The validity and efficiency of the present technique are verified by comparisons of present results with the previous ones determined by other researchers.

Post-Buckling of Functionally Graded Cylindrical Shells

2007 ◽  
Author(s):  
Recep Gunes ◽  
M. Kemal Apalak ◽  
H. Abdullah Tasdemir
Keyword(s):  
Shell Thickness ◽  
Cylindrical Shells ◽  
Functionally Graded ◽  
Minor Effect ◽  
Power Law Distribution ◽  
Compositional Gradient ◽  
Concentrated Load ◽  
Layer Number ◽  
Post Buckling ◽  
A Minor

In this study, the post-buckling analysis of functionally graded cylindrical shells was carried out using the non-linear finite element method. The longitudinal shell edges were hinged under a central transverse concentrated load. The shells were composed of ceramic (Al2O3) and metal (Ni) phases and the mechanical properties at the region between the metal and ceramic layers vary continuously through the shell thickness according to a power-law distribution of the volume fractions of the constituents. The arc-length method was implemented. The effects of material composition and layer number as well as various shell thicknesses on the post-buckling response of the functionally graded cylindrical shells were investigated. The functionally graded shells exhibit both snap-through and snap-back post buckling behaviours. The layer number through the shell thickness has a minor effect on the post-buckling behaviour whereas the compositional gradient exponent varies from 0.1 to 10.0 the snap-through behaviour becomes more obvious whilst both the snap-through and snap-back behaviours appear for a thinner shell.

Creep Buckling Analyses of Circular Cylindrical Shells Under Axial Compression—Bifurcation Buckling Analysis by the Finite Element Method

1987 ◽  
Vol 109 (2) ◽  
pp. 179-183 ◽  
Author(s):  
N. Miyazaki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Axial Compression ◽  
Circular Cylindrical Shell ◽  
Cylindrical Shells ◽  
The Finite Element Method ◽  
Bifurcation Buckling ◽  
Creep Buckling ◽  
Circular Cylindrical Shells

The finite element method is applied to the creep buckling of circular cylindrical shells under axial compression. Not only the axisymmetric mode but also the bifurcation mode of the creep buckling are considered in the analysis. The critical time for creep buckling is defined as either the time when a slope of a displacement versus time curve becomes infinite or the time when the bifurcation buckling occurs. The creep buckling analyses are carried out for an infinitely long and axially compressed circular cylindrical shell with an axisymmetric initial imperfection and for a finitely long and axially compressed circular cylindrical shell. The numerical results are compared with available analytical ones and experimental data.

scholarly journals Natural frequencies analysis of functionally graded circular cylindrical shells

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Nabeel T. Alshabatat ◽  
Mohammad Zannon
Keyword(s):  
Shear Deformation ◽  
Power Law ◽  
Shell Theory ◽  
Natural Frequencies ◽  
Cylindrical Shells ◽  
Functionally Graded ◽  
Radius Ratio ◽  
Third Order ◽  
The Third ◽  
Circular Cylindrical Shells

In the present work, a study on natural frequencies of functionally graded materials (FGM) circular cylindrical shells is presented. TheFGM is considered to be a mixture of two materials. The volumetric fractions are considered to vary in the radial direction (i.e., through the thickness) in compliance with a conventional power-law distribution. The equivalent material properties are estimated based on the Voigt model. The analysis of the FGM cylindrical shells is performed using the third-order shear deformation shell theory and the principle of virtual displacements. Moreover, the third-order shear deformation shell theory coupled with Carrera’s unified formulation is applied for the derivation of the governing equations associated with the free vibration of circular cylindrical shells. The accuracy of this method is examined by comparing the obtained numerical results with other previously published results. Additionally, parametric studies are performed for FGM cylindrical shells with several boundary conditions in order to show the effect of several design variables on the natural frequencies such as the power-law exponent, the circumferential wave number, the length to radius ratio and the thickness to radius ratio.

scholarly journals Vibration analysis of FG cylindrical shells with power-law index using discrete singular convolution technique

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Kadir Mercan ◽  
Çiğdem Demir ◽  
Ömer Civalek
Keyword(s):  
Power Law ◽  
Volume Fraction ◽  
Constitutive Relations ◽  
Cylindrical Shells ◽  
Functionally Graded ◽  
Graded Material ◽  
Circular Cylindrical Shells ◽  
Discrete Singular Convolution ◽  
Power Law Index ◽  
Free Vibration Response

AbstractIn the present manuscript, free vibration response of circular cylindrical shells with functionally graded material (FGM) is investigated. The method of discrete singular convolution (DSC) is used for numerical solution of the related governing equation of motion of FGM cylindrical shell. The constitutive relations are based on the Love’s first approximation shell theory. The material properties are graded in the thickness direction according to a volume fraction power law indexes. Frequency values are calculated for different types of boundary conditions, material and geometric parameters. In general, close agreement between the obtained results and those of other researchers has been found.

Reduced-Order Nonlinear Modal Equations of Circular Cylindrical Shells Based on the Finite-Element Method

2004 ◽  
Author(s):  
Yukinori Kobayashi ◽  
Tomoaki Furukawa ◽  
Gen Yamada
Keyword(s):  
Finite Element ◽  
Circular Cylindrical Shell ◽  
Equations Of Motion ◽  
Cylindrical Shells ◽  
Nonlinear Finite Element ◽  
Element Analysis ◽  
Reduced Order ◽  
Finite Element Equation ◽  
Displacement Vectors ◽  
Circular Cylindrical Shells

This paper presents a procedure to derive reduced-order nonlinear modal equations of circular cylindrical shells. Modal analysis is applied to the nonlinear finite element equation by using base vectors obtained by the finite element analysis. Reduced-order modal equations are derived by transforming the equations of motion from the physical coordinates to the modal coordinates. Base vectors for the transformation consist of dominant linear eigenmodes and nonlinear displacement vectors derived approximately from the nonlinear finite element equation. Asymmetry of the deformation of the circular cylindrical shell with respect to its neutral surface is taken into consideration to determine the base vectors. Numerical results show good agreement with those presented in other papers.

scholarly journals Finite Element Formulation for the Large-Amplitude Vibrations of FG Beams

2014 ◽  
Vol 61 (3) ◽  
pp. 469-482 ◽  
Author(s):  
Mehdi Javid ◽  
Milad Hemmatnezhad
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Power Law ◽  
Large Amplitude ◽  
Free Vibration Analysis ◽  
Functionally Graded ◽  
Finite Element Formulation ◽  
Geometrical Parameters ◽  
Element Formulation ◽  
Vibration Frequencies

Abstract On the basis of Euler-Bernoulli beam theory, the large-amplitude free vibration analysis of functionally graded beams is investigated by means of a finite element formulation. The von Karman type nonlinear strain-displacement relationship is employed where the ends of the beam are constrained to move axially. The material properties are assumed to be graded in the thickness direction according to the power-law and sigmoid distributions. The finite element method is employed to discretize the nonlinear governing equations, which are then solved by the direct numerical integration technique in order to obtain the nonlinear vibration frequencies of functionally graded beams with different boundary conditions. The influences of power-law index, vibration amplitude, beam geometrical parameters and end supports on the free vibration frequencies are studied. The present numerical results compare very well with the results available from the literature where possible.

Three-dimensional static analysis of thick functionally graded plates using graded finite element method

2013 ◽  
Vol 228 (8) ◽  
pp. 1275-1285 ◽  
Author(s):  
Hassan Zafarmand ◽  
Mehran Kadkhodayan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Power Law ◽  
Three Dimensional ◽  
Functionally Graded ◽  
Published Data ◽  
Power Law Distribution ◽  
Various Boundary Conditions ◽  
Graded Finite Element Method ◽  
Element Method

In this paper, a thick functionally graded plate based on three-dimensional equations of elasticity and subjected to nonuniform transverse loading is considered. The Young’s modulus of the plate is assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents and the Poisson’s ratio is assumed to be constant. Three-dimensional graded finite element method based on Rayleigh–Ritz energy formulation has been applied to study the static response of the plate. The plate deflection and in-plane stress for different values of the power law exponent, thickness-to-length ratio, and various boundary conditions have been investigated. To verify the presented method and data, the results are compared to published data.

Relationship between Bending Solutions of FGM and Homogenous Circular Cylindrical Shells

2013 ◽  
Vol 353-356 ◽  
pp. 3236-3242
Author(s):  
Ze Qing Wan ◽  
Shi Rong Li
Keyword(s):  
Cylindrical Shell ◽  
Numerical Solutions ◽  
Volume Fraction ◽  
Circular Cylindrical Shell ◽  
Cylindrical Shells ◽  
Continuous Functions ◽  
Functionally Graded ◽  
Graded Materials ◽  
Graded Material ◽  
Circular Cylindrical Shells

Based on the Loves shell theory, relationship between bending solutions of functionally graded materials (FGM) and homogenous circular cylindrical shells was studied. By comparing the displacement-type governing equations for axially symmetrically bending of FGM and homogenous circular cylindrical shells, an analogous transform relation between the deflections of FGM circular cylindrical shell and those of homogenous one was obtained. By giving the material properties of FGM circular cylindrical shell changing as continuous functions in the thickness direction, the corresponding transition factor between the solutions of the two kind circular cylindrical shells were derived, which reflect the non-uniform properties of the functionally graded material circular cylindrical shell. Numerical example shows that the numerical solutions of the maximum of non-dimensional deflections are almost in agreement with the transformational solutions whennequals approximately 5, wherenis the volume fraction index. As a result, solutions for axially symmetrically bending of a non-homogenous circular cylindrical shell can be reduced to that of a homogenous one and the calculation of the transformation factors.

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