Frequency analysis of functionally graded material cylindrical shells with various volume fraction laws

Author(s):  
S H Arshad ◽  
M N Naeem ◽  
N Sultana

In the current paper a frequency analysis is performed for functionally graded material (FGM) circular cylindrical shells. A comparative study of shell frequencies is given for algebraic polynomial, exponential, and trigonometric volume fraction laws. An FGM shell considered here is structured from two materials. Love's thin shell theory is utilized for strain-displacement and curvature-displacement relations. The Rayleigh-Ritz method is employed to derive the frequency equation in the form of eigenvalue problem. Natural frequencies are evaluated for a shell with simply supported edge conditions. The axial modal dependence is approximated by circular trigonometric functions. Theoretical results are compared with those available in the literature for the validity of the present methodology.

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 587-600
Author(s):  
Madiha Ghamkhar ◽  
Muhammad Nawaz Naeem ◽  
Muhammad Imran ◽  
Constantinos Soutis

Abstract In this work, we study vibrations of three-layered cylindrical shells with one ring support along its length. Nature of material of the central layer is a functionally graded material (FGM) type. The considered FGM is of stainless steel and nickel. The internal and external layers are presumed to be made of isotropic material i.e., aluminum. The functionally graded material composition of the center layer is assorted by three volume fraction laws (VFL) which are represented by mathematical expressions of polynomial, exponential and trigonometric functions. The implementation of Rayleigh-Ritz method has been done under the Sanders’ shell theory to obtain the shell frequency equation. Natural frequencies (NFs) are attained for the present model problem under six boundary conditions. Use of characteristic beam functions is made for the estimation of the dependence of axial modals. The impact of layer material variations with ring support is considered for many ring positions. Also the effect of volume fraction laws is investigated upon vibration characteristics. This investigation is performed for various physical parameters. Numerous comparisons of values of shell frequencies have been done with available models of such types of results to verify accuracy of the present formulation and demonstrate its numerical efficiency.


Author(s):  
Mahdi Saeidifar ◽  
Abdolreza Ohadi

In this study, the free vibration of partially fluid-filled functionally graded material (FGM) cylindrical shells with arbitrary boundary conditions has been investigated using the Rayleigh-Ritz method. The analysis has been carried out with strain-displacement relations from Love’s thin shell theory and the contained fluid is assumed irrotational, incompressible and inviscid. The Rayleigh-Ritz method is based on the energy parameters, so after determining the kinetic and potential energies of FGM shell filled with fluid, the eigenvalue problem has been obtained. To demonstrate the validity and accuracy of the obtained theoretical results, comparison has been made with the previous published results and also with the finite element results for the empty and partially fluid-filled shells. Finally, the effects of fluid level and power-law exponent on natural frequencies of partially fluid-filled FGM shells have been investigated.


2019 ◽  
Vol 134 ◽  
pp. 189-202 ◽  
Author(s):  
C.S. Huang ◽  
H.T. Lee ◽  
P.Y. Li ◽  
K.C. Hu ◽  
C.W. Lan ◽  
...  

2012 ◽  
Vol 376 (45) ◽  
pp. 3351-3358 ◽  
Author(s):  
Huijie Shen ◽  
Jihong Wen ◽  
Michael P. Païdoussis ◽  
Dianlong Yu ◽  
Meisam Asgari ◽  
...  

2010 ◽  
Vol 19 (2) ◽  
pp. 096369351001900 ◽  
Author(s):  
F. Ebrahimi ◽  
H.A. Sepiani

In this study, a formulation for the free vibration and buckling of cylindrical shells made of functionally graded material (FGM) subjected to combined static and periodic axial loadings are presented. The properties are temperature dependent and graded in the thickness direction according to a volume fraction power law distribution. The analysis is based on two different methods of first-order shear deformation theory (FSDT) considering the transverse shear strains and the rotary inertias and the classical shell theory (CST). The results obtained show that the effect of transverse shear and rotary inertias on vibration and buckling of functionally graded cylindrical shells is dependent on the material composition, the temperature environment, the amplitude of static load, the deformation mode, and the shell geometry parameters.


2018 ◽  
Vol 18 (11) ◽  
pp. 1850138 ◽  
Author(s):  
Yueyang Han ◽  
Xiang Zhu ◽  
Tianyun Li ◽  
Yunyan Yu ◽  
Xiaofang Hu

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.


2014 ◽  
Vol 627 ◽  
pp. 57-60 ◽  
Author(s):  
Wasim M.K. Helal ◽  
Dong Yan Shi

Functionally graded materials (FGMs) have become helpful in our engineering applications. Analysis of functionally graded material (FGM) plate during debonding case with different boundary conditions is the main purpose of this investigation. Elastic modulus (E) of functionally graded (FG) plate is assumed to vary continuously throughout the height of the plate, according the volume fraction of the constituent materials based on a modified sigmoid function, but the value of Poisson coefficient is constant. In this research, the finite element method (FEM) is used in order to show the shape of a plate made of FGM during debonding case with different boundary conditions. In the present investigation, the displacement value applied to the FGM plate is changed in order to find the relationship between the maximum von Mises stress and the displacement. Also, the relationship between the maximum shear stress and the displacement is carried out in the present work. The material gradient indexes of the FGM plate are changed from 1 to 10. The stress distributions around the debonding zone with all the material gradient indexes of the FGM plate are investigated in this work.


2012 ◽  
Vol 12 (02) ◽  
pp. 311-335 ◽  
Author(s):  
X. Q. HE ◽  
L. LI ◽  
S. KITIPORNCHAI ◽  
C. M. WANG ◽  
H. P. ZHU

Based on an inextensional two-parameter analytical model for cylindrical shells, bi-stable analyses were carried out on laminated functionally graded material (FGM) shells with various layups of fibers. Properties of FGM shells are functionally graded in the thickness direction according to a volume fraction power law distribution. The effects of constituent volume fractions of FGM matrix are examined on the curvature and twist of laminated FGM shells. The results reveal that the optimum combination of constituents of FGM matrix can be obtained for the maximum twist of FGM shells with antisymmetric layups, which helps the design of deployable structures. The effects of Young's modulus of fibers and the symmetry of layups on bi-stable behaviors are also discussed in detail.


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