Natural Vibration of Functionally Graded Cylindrical Shells With Infinite and Finite Lengths

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Zhiyuan Cao ◽  
Shougao Tang
Keyword(s):  
Functionally Graded Material ◽  
Mode Shape ◽  
Natural Vibration ◽  
Separation Of Variables ◽  
Cylindrical Shells ◽  
Analytic Solutions ◽  
Variable Coefficients ◽  
Functionally Graded ◽  
Graded Material ◽  
Membrane Bending

Upon the basic theory of functionally graded material cylindrical shell, the original 3-D foundational equations with variable coefficients are transformed into anisotropic and membrane-bending coupling 2-D equations with constant coefficients. The separation-of-variables mode shape functions in axial and circumferential directions for cylindrical shells with infinite and finite lengths are proposed for analytic solutions, which satisfy the basic differential equations, of natural vibration. The general approach presented in the paper for the solutions of natural frequency and mode shape of functionally graded cylindrical shells can be applied to cylindrical shells with any kind of functionally graded material, different length, and boundary conditions.

Exact solution by dynamic stiffness method for the natural vibration of porous functionally graded plate considering neutral surface

2021 ◽  
pp. 146442072098817
Author(s):  
Md. Imran Ali ◽  
Mohammad Sikandar Azam
Keyword(s):  
Power Law ◽  
Functionally Graded Material ◽  
Stiffness Matrix ◽  
Natural Vibration ◽  
Dynamic Stiffness ◽  
Functionally Graded ◽  
Neutral Surface ◽  
Functionally Graded Plate ◽  
Dynamic Stiffness Matrix ◽  
Graded Material

This paper presents the formulation of dynamic stiffness matrix for the natural vibration analysis of porous power-law functionally graded Levy-type plate. In the process of formulating the dynamic stiffness matrix, Kirchhoff-Love plate theory in tandem with the notion of neutral surface has been taken on board. The developed dynamic stiffness matrix, a transcendental function of frequency, has been solved through the Wittrick–Williams algorithm. Hamilton’s principle is used to obtain the equation of motion and associated natural boundary conditions of porous power-law functionally graded plate. The variation across the thickness of the functionally graded plate’s material properties follows the power-law function. During the fabrication process, the microvoids and pores develop in functionally graded material plates. Three types of porosity distributions are considered in this article: even, uneven, and logarithmic. The eigenvalues computed by the dynamic stiffness matrix using Wittrick–Williams algorithm for isotropic, power-law functionally graded, and porous power-law functionally graded plate are juxtaposed with previously referred results, and good agreement is found. The significance of various parameters of plate vis-à-vis aspect ratio ( L/b), boundary conditions, volume fraction index ( p), porosity parameter ( e), and porosity distribution on the eigenvalues of the porous power-law functionally graded plate is examined. The effect of material density ratio and Young’s modulus ratio on the natural vibration of porous power-law functionally graded plate is also explained in this article. The results also prove that the method provided in the present work is highly accurate and computationally efficient and could be confidently used as a reference for further study of porous functionally graded material plate.

Control of sound and vibration for cylindrical shells by utilizing a periodic structure of functionally graded material

2012 ◽  
Vol 376 (45) ◽  
pp. 3351-3358 ◽  
Author(s):  
Huijie Shen ◽  
Jihong Wen ◽  
Michael P. Païdoussis ◽  
Dianlong Yu ◽  
Meisam Asgari ◽  
...  
Keyword(s):  
Periodic Structure ◽  
Functionally Graded Material ◽  
Cylindrical Shells ◽  
Functionally Graded ◽  
Graded Material

Free Vibration and Elastic Critical Load of Functionally Graded Material Thin Cylindrical Shells Under Internal Pressure

2018 ◽  
Vol 18 (11) ◽  
pp. 1850138 ◽  
Author(s):  
Yueyang Han ◽  
Xiang Zhu ◽  
Tianyun Li ◽  
Yunyan Yu ◽  
Xiaofang Hu
Keyword(s):  
Cylindrical Shell ◽  
Free Vibration ◽  
Internal Pressure ◽  
Critical Load ◽  
Natural Frequency ◽  
Functionally Graded Material ◽  
Present Method ◽  
Cylindrical Shells ◽  
Functionally Graded ◽  
Graded Material

An analytical approach for predicting the free vibration and elastic critical load of functionally graded material (FGM) thin cylindrical shells filled with internal pressured fluid is presented in this study. The vibration of the FGM cylindrical shell is described by the Flügge shell theory, where the internal static pressure is considered as the prestress term in the shell equations. The motion of the internal fluid is described by the acoustic wave equation. The natural frequencies of the FGM cylindrical shell under different internal pressures are obtained with the wave propagation method. The relationship between the internal pressure and the natural frequency of the cylindrical shell is analyzed. Then the linear extrapolation method is employed to obtain the elastic critical load of the FGM cylindrical shell from the condition that the increasing pressure has resulted in zero natural frequency. The accuracy of the present method is verified by comparison with the published results. The effects of gradient index, boundary conditions and structural parameters on the elastic critical load of the FGM cylindrical shell are discussed. Compared with the experimental and numerical analyses based on the external pressure, the present method is simple and easy to carry out.

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.

Vibration frequency of thick functionally graded material cylindrical shells with fully homogeneous equation and third-order shear deformation theory under thermal environment

2020 ◽  
pp. 107754632095166
Author(s):  
Chih-Chiang Hong
Keyword(s):  
Shear Deformation ◽  
Functionally Graded Material ◽  
Deformation Theory ◽  
Cylindrical Shells ◽  
Homogeneous Equation ◽  
Nonlinear Coefficient ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Third Order ◽  
Graded Material

The effects of third-order shear deformation theory and varied shear correction coefficient on the vibration frequency of thick functionally graded material cylindrical shells with fully homogeneous equation under thermal environment are investigated. The nonlinear coefficient term of displacement field of third-order shear deformation theory is included to derive the fully homogeneous equation under free vibration of functionally graded material cylindrical shells. The determinant of the coefficient matrix in dynamic equilibrium differential equations under free vibration can be represented into the fully fifth-order polynomial equation, thus the natural frequency can be found. Two parametric effects of environment temperature and functionally graded material power law index on the natural frequency of functionally graded material thick cylindrical shells with and without the nonlinear coefficient term of displacement fields are computed and investigated.

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