scholarly journals Thermal buckling of imperfect functionally graded cylindrical shells according to Wan-Donnell model

2008 ◽  
Vol 30 (3) ◽  
Author(s):  
Hoang Van Tung ◽  
Nguyen Dinh Duc
Keyword(s):  
Cylindrical Shells ◽  
Closed Form Solution ◽  
Form Solution ◽  
Thermal Buckling ◽  
Functionally Graded ◽  
Thermal Loads ◽  
Geometrical Imperfection ◽  
Graded Material ◽  
Nonlinear Temperature ◽  
Power Law Index

A thermal buckling analysis of imperfect circular cylindrical shells of functionally graded material is considered. The material properties are assumed varying as a power form of thickness coordinate variable. The Donnell equilibrium and stability equations are considered and the Wan-Donnell model for initial geometrical imperfection is adopted. The thermal loads include the uniform temperature rise and nonlinear temperature change across the thickness of shell. A closed form solution for the thermal buckling of simply supported cylindrical FG shell under the described thermal loads is obtained. The influences of the relative thickness, the imperfection size and the power law index on buckling thermal loads are all discussed.

Nonlinear stability analysis of stiffened functionally graded material sandwich cylindrical shells with general Sigmoid law and power law in thermal environment using third-order shear deformation theory

2017 ◽  
Vol 21 (3) ◽  
pp. 938-972 ◽  
Author(s):  
Dao Van Dung ◽  
Nguyen Thi Nga ◽  
Pham Minh Vuong
Keyword(s):  
Shear Deformation ◽  
Power Law ◽  
Nonlinear Stability ◽  
Functionally Graded Material ◽  
Shell Theory ◽  
Cylindrical Shells ◽  
Functionally Graded ◽  
Thermal Loads ◽  
Third Order ◽  
Graded Material

This paper investigates analytically nonlinear buckling and postbuckling of functionally graded sandwich circular thick cylindrical shells filled inside by Pasternak two-parameter elastic foundations under thermal loads and axial compression loads. Shells are reinforced by closely spaced functionally graded material (FGM) rings and stringers. The temperature field is taken into account. Two general Sigmoid law and general power law, with four models of stiffened FGM sandwich cylindrical shell, are proposed. Using the Reddy’s third-order shear deformation shell theory (TSDT), stress function, and Lekhnitsky’s smeared stiffeners technique, the governing equations are derived. The closed form to determine critical axial load and postbuckling load-deflection curves are obtained by the Galerkin method. The effects of the face sheet thickness to total thickness ratio, stiffener, foundation, material, and dimensional parameters on critical thermal loads, critical mechanical loads and postbuckling behavior of shells are analyzed. In addition, this paper shows that for thin shells we can use the classical shell theory to investigate stability behavior of shell, but for thicker shells the use of TSDT for analyzing nonlinear stability of shell is necessary and suitable.

EFFECTS OF MATERIAL GRADIENTS ON ONSET OF YIELD IN FGM ROTATING THICK CYLINDRICAL SHELLS

2014 ◽  
Vol 06 (04) ◽  
pp. 1450038 ◽  
Author(s):  
PARISA FATEHI ◽  
MOHAMMAD ZAMANI NEJAD
Keyword(s):  
Material Properties ◽  
Poisson’S Ratio ◽  
Cylindrical Shells ◽  
Closed Form Solution ◽  
External Pressure ◽  
Density Variation ◽  
Form Solution ◽  
Functionally Graded ◽  
Poisson's Ratio ◽  
Critical Material

In this paper, a closed-form solution to determine location of yield in rotating thick-walled cylindrical shells made of functionally graded materials (FGMs) using both Tresca's and von Mises yield criteria is presented. The cylindrical shell is subjected to uniform internal and external pressure. The material properties are assumed to vary according to power law functions and the Poisson's ratio is assumed to be constant. Moreover, the plane strain condition is used to drive expressions for distributions of stresses and radial displacement. In the present work, rotation, internal and external pressure and variation of material properties are considered simultaneously. To the best of authors' knowledge, in previous researches in which onset of yield is investigated, variation of material density is ignored, while density is not constant in FGM rotating thick cylindrical shells. Our results show that the density variation has a significant effect on the stress distributions. Our research has also tried to explain the effect of different Poisson's ratio on the value of the critical material parameter.

Mechanical Buckling of Functionally Graded Cylindrical Shells Based on the First Order Shear Deformation Theory

2007 ◽  
Author(s):  
Ramin Narimani ◽  
Mehdi Karami Khorramabadi ◽  
Payam Khazaeinejad
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Cylindrical Shells ◽  
Closed Form Solution ◽  
Shear Deformation Theory ◽  
Form Solution ◽  
Functionally Graded ◽  
Buckling Load ◽  
Critical Buckling Load ◽  
First Order

Buckling analysis of simply supported functionally graded cylindrical shells under mechanical loads is presented in this paper. The Young’s modulus of the shell is assumed to vary as a power form of the thickness coordinate variable. The shell is assumed to be under three types of mechanical loadings, namely, axial compression, uniform external lateral pressure, and hydrostatic pressure loading. The equilibrium and stability equations are derived based on the first order shear deformation theory. Resulting equations are employed to obtain the closed-form solution for the critical buckling load. The influences of dimension ratio, relative thickness and the functionally graded index on the critical buckling load are studied. The results are compared with the known data in the literature.

Transient Response of Functionally Graded Material Circular Cylindrical Shells with Magnetostrictive Layer

2016 ◽  
Vol 32 (4) ◽  
pp. 473-478
Author(s):  
C.-C. Hong
Keyword(s):  
Transient Response ◽  
Functionally Graded Material ◽  
Cylindrical Shells ◽  
Functionally Graded ◽  
Normal Displacement ◽  
Control Gain ◽  
Graded Material ◽  
Circular Cylindrical Shells ◽  
Generalized Differential ◽  
Power Law Index

AbstractThe generalized differential quadrature (GDQ) method is used to investigate the transient response of magnetostrictive functionally graded material (FGM) circular cylindrical shells. The effects of control gain value, thermal load temperature and power-law index on transient responses of dominant normal displacement and thermal stress are analyzed. With velocity feedback and suitable product values of coil constant by control gain in the magnetostrictive FGM shells can reduce the transient amplitude of displacement into a smaller value.

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.

Thermal Buckling of Functionally Graded Sandwich Beams

2019 ◽  
Vol 1156 ◽  
pp. 43-59 ◽  
Author(s):  
Ahmed Amine Daikh ◽  
Mohamed Guerroudj ◽  
Mohamed El Adjrami ◽  
Abdelkader Megueni
Keyword(s):  
Thermal Loading ◽  
Beam Theory ◽  
Form Solution ◽  
Thermal Buckling ◽  
Functionally Graded ◽  
Sigmoid Function ◽  
Sandwich Beams ◽  
Nonlinear Temperature ◽  
Inhomogeneity Parameter ◽  
Nonlinear Distribution

Thermal buckling of new model of functionally graded (FG) sandwich beams is presented in this study. Material properties and thermal expansion coefficient of FG sheets are assumed to vary continuously along the thickness according to either power-law (P-FGM) or sigmoid function (S-FGM) in terms of the volume fractions of the constituents. Equations of stability are derived based on the generalized higher-order shear deformation beam theory. Thermal loads are supposed to be constant, linear or nonlinear distribution along the thickness direction. An accurate form solution for nonlinear temperature variation through the thickness of S-FGM and P-FGM sandwich beams is presented. Numerical examples are presented to examine the influence of thickness ratio, the inhomogeneity parameter and the thermal loading kinds on the thermal buckling response of various types of FG sandwich beams.

Elastic Green’s Functions for a Specific Graded Material With a Quadratic Variation of Elasticity

2010 ◽  
Vol 78 (2) ◽  
Author(s):  
Zifeng F. Yuan ◽  
Huiming M. Yin
Keyword(s):  
Green's Functions ◽  
Green’S Functions ◽  
Early Stage ◽  
Closed Form Solution ◽  
Aging Effect ◽  
Logarithmic Potential ◽  
Form Solution ◽  
Functionally Graded ◽  
Quadratic Variation ◽  
Graded Material

In this work, Green’s functions for unbounded elastic domain in a functionally graded material with a quadratic variation of elastic moduli and constant Poisson’s ratio of 0.25 are derived for both two-dimensional (2D) and three-dimensional (3D) cases. The displacement fields caused by a point force are derived using the logarithmic potential and the Kelvin solution for 2D and 3D cases, respectively. For a circular (2D) or spherical (3D) bounded domain, analytical solutions are provided by superposing the above solutions and corresponding elastic general solutions. This closed form solution is valuable for elastic analysis with material stiffness variations caused by temperature, moisture, aging effect, or material composition, and it can be used to perform early stage verification of more complex models of functionally graded materials. Comparison of theoretical solution and finite element method results demonstrates the application and accuracy of this solution.

Elastic Foundation Analysis of Uniformly Loaded Functionally Graded Viscoelastic Sandwich Plates

2012 ◽  
Vol 28 (3) ◽  
pp. 439-452 ◽  
Author(s):  
A. M. Zenkour ◽  
M. Sobhy
Keyword(s):  
Power Law ◽  
Sandwich Plate ◽  
Plate Theory ◽  
Functionally Graded ◽  
Sandwich Plates ◽  
Equilibrium Equations ◽  
Graded Material ◽  
Plate Aspect Ratio ◽  
Type V ◽  
Power Law Index

AbstractThis paper deals with the static response of simply supported functionally graded material (FGM) viscoelastic sandwich plates subjected to transverse uniform loads. The FG sandwich plates are considered to be resting on Pasternak's elastic foundations. The sandwich plate is assumed to consist of a fully elastic core sandwiched by elastic-viscoelastic FGM layers. Material properties are graded according to a power-law variation from the interfaces to the faces of the plate. The equilibrium equations of the FG sandwich plate are given based on a trigonometric shear deformation plate theory. Using Illyushin's method, the governing equations of the viscoelastic sandwich plate can be solved. Parametric study on the bending analysis of FG sandwich plates is being investigated. These parameters include (i) power-law index, (ii) plate aspect ratio, (iii) side-to-thickness ratio, (iv) loading type, (v) foundation stiffnesses, and (vi) time parameter.

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