scholarly journals Nonlinear response of doubly curved sandwich panels with CNT-reinforced composite core and elastically restrained edges subjected to external pressure in thermal environments

Author(s):  
Hoang Van Tung ◽  
Dao Nhu Mai ◽  
Vu Thanh Long

An analytical investigation on the nonlinear response of doubly curved panels constructed from homogeneous face sheets and carbon nanotube reinforced composite (CNTRC) core and subjected to external pressure in thermal environments is presented in this paper. Carbon nanotubes (CNTs) are reinforced into the core layer through uniform or functionally graded distributions. The properties of constituents are assumed to be temperature dependent and effective properties of CNTRC are determined using an extended rule of mixture. Governing equations are established within the framework of first order shear deformation theory taking into account geometrical imperfection, von Kármán–Donnell nonlinearity, panel-foundation interaction and elasticity of tangential edge restraints. These equations are solved using approximate analytical solutions and Galerkin method for simply supported panels. The results reveal that load carrying capacity of sandwich panels is stronger when boundary edges are more rigorously restrained and face sheets are thicker. Furthermore, elevated temperature has deteriorative and beneficial influences on the load bearing capability of sandwich panels with movable and restrained edges, respectively.

Author(s):  
Hoang Van Tung ◽  
Vu Thanh Long

An analytical investigation on the buckling and postbuckling behavior of carbon nanotube reinforced composite (CNTRC) sandwich cylindrical panels exposed to thermal environments and subjected to uniform axial compression is presented in this paper. Beside sandwich model with CNTRC face sheets in the literature, the present work suggests a sandwich model with CNTRC core layer and homogeneous face sheets. Carbon nanotubes (CNTs) are reinforced into matrix phase through uniform or functionally graded distributions. Effective properties of nanocomposite layers are determined according to extended rule of mixture. Formulations are based on the first order shear deformation theory taking into account Von Karman-Donnell nonlinearity. Approximate solutions are assumed to satisfy simply supported boundary conditions and Galerkin method is used to derive the closed-form expression of nonlinear load-deflection relation from which buckling loads and postbuckling paths are determined. Numerical examples are carried out and interesting remarks are given.


2017 ◽  
Vol 20 (8) ◽  
pp. 974-1008 ◽  
Author(s):  
Hoang Van Tung

This paper investigates the nonlinear response of doubly curved functionally graded material sandwich panels resting on elastic foundations, exposed to thermal environments and subjected to uniform external pressure. The material properties of both face sheets and core layer are assumed to be temperature dependent, and effective material properties of functionally graded material layers are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. Formulations are based on first-order shear deformation shell theory taking geometrical nonlinearity, initial geometrical imperfection, Pasternak type elastic foundations, and tangential edge constraints into consideration. Approximate solutions are assumed to satisfy simply supported boundary conditions and Galerkin procedure is applied to derive expressions of buckling loads and nonlinear load–deflection relation. The effects of material, geometry and foundation parameters, face sheet thickness ratio, initial geometrical imperfection, thermal environments and degree of tangential restraint of edges on the snap-through instability, and nonlinear response of spherical and cylindrical functionally graded material sandwich panels are analyzed and discussed in detail.


Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 79 ◽  
Author(s):  
Masoud Mohammadi ◽  
Mohammad Arefi ◽  
Rossana Dimitri ◽  
Francesco Tornabene

This study analyses the two-dimensional thermo-elastic response of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) cylindrical pressure vessels, by applying the third-order shear deformation theory (TSDT). The effective properties of FG-CNTRC cylindrical pressure vessels are computed for different patterns of reinforcement, according to the rule of mixture. The governing equations of the problem are derived from the principle of virtual works and are solved as a classical eigenproblem under the assumption of clamped supported boundary conditions. A large parametric investigation aims at showing the influence of some meaningful parameters on the thermo-elastic response, such as the type of pattern, the volume fraction of CNTs, and the Pasternak coefficients related to the elastic foundation.


2018 ◽  
Vol 90 (1) ◽  
pp. 11-23 ◽  
Author(s):  
Kulmani Mehar ◽  
Subrata Kumar Panda

Purpose The purpose of this paper is to develop a general mathematical model for the evaluation of the theoretical flexural responses of the functionally graded carbon nanotube-reinforced composite doubly curved shell panel using higher-order shear deformation theory with thermal load. It is well-known that functionally graded materials are a multidimensional problem, and the present numerical model is also capable of solving the flexural behaviour of different shell panel made up of carbon nanotube-reinforced composite with adequate accuracy in the absence of experimentation. Design/methodology/approach In this current paper, the responses of the single-walled carbon nanotube-reinforced composite panel is computed numerically using the proposed generalised higher-order mathematical model through a homemade computer code developed in MATLAB. The desired flexural responses are computed numerically using the variational method. Findings The validity and the convergence behaviour of the present higher-order model indicate the necessity for the analysis of multidimensional structure under the combined loading condition. The effect of various design parameters on the flexural behaviour of functionally graded carbon nanotube doubly curved shell panel are examined to highlight the applicability of the presently proposed higher-order model under thermal environment. Originality/value In this paper, for the first time, the static behaviour of functionally graded carbon nanotube-reinforced composite doubly curved shell panel is analysed using higher-order shear deformation theory. The properties of carbon nanotube and the matrix material are considered to be temperature dependent. The present model is so general that it is capable of solving various geometries from single curve to doubly curved panel, including the flat panel.


Author(s):  
Le Thi Nhu Trang ◽  
Hoang Van Tung

Geometrically nonlinear response of doubly curved panels reinforced by carbon nanotubes exposed to thermal environments and subjected to uniform external pressure are presented in this paper. Carbon nanotubes are reinforced into isotropic matrix through uniform and functionally graded distributions. Material properties of constituents are assumed to be temperature dependent, and effective elastic moduli of carbon nanotube-reinforced composite are determined according to an extended rule of mixture. Basic equations for carbon nanotube-reinforced composite doubly curved panels are established within the framework of first-order shear deformation theory. Analytical solutions are assumed, and Galerkin method is used to derive closed-form expressions of nonlinear load–deflection relation. Separate and combined effects of carbon nanotube distribution and volume fraction, elasticity of in-plane constraint, elevated temperature, initial imperfection, geometrical ratios and stiffness of elastic foundations on the nonlinear stability of nanocomposite doubly curved panels are analyzed through numerical examples.


2018 ◽  
Vol 53 (9) ◽  
pp. 1159-1179 ◽  
Author(s):  
Tao Fu ◽  
Zhaobo Chen ◽  
Hongying Yu ◽  
Zhonglong Wang ◽  
Xiaoxiang Liu

The present study is concerned with static and free vibration analyses of laminated functionally graded carbon nanotube reinforced composite rectangular plates on elastic foundation based on nth-order shear deformation theory. Four types of carbon nanotubes distributions along the plate thickness are considered, which include uniformly distributed and three other functionally graded distributions. Governing differential equations are derived by means of Hamilton’s principle. The differential quadrature method is developed to formulate the problem, and rapid convergence is observed in this study. A numerical comparison with available results in the literature is carried out to show the validity of the proposed theory. Furthermore, effects of the carbon nanotubes volume fraction, thickness side ratio, aspect ratio, foundation parameters, different thermal environments, the number of layers, lamination angle, boundary condition, and carbon nanotubes distribution types on the static response of laminated functionally graded carbon nanotube reinforced composite plates are also investigated.


2019 ◽  
Vol 22 (5) ◽  
pp. 1681-1706 ◽  
Author(s):  
Tao Fu ◽  
Zhaobo Chen ◽  
Hongying Yu ◽  
Qingjun Hao ◽  
Yanzheng Zhao

The present study is concerned with vibro-acoustic behavior analyses of laminated functionally graded carbon nanotube reinforced composite plates based on Reddy’s higher order shear deformation theory. Four types of carbon nanotubes distributions along the plate thickness are considered, which include uniformly distributed and three other functionally graded distributions. Governing differential equations are derived by means of Hamilton’s principle. The sound pressure and radiation efficiency are calculated with Rayleigh integral. A numerical comparison with available results in the literature is carried out to show the validity of the present model. Furthermore, effects of the carbon nanotubes volume fraction, different thermal environments, lamination angle and carbon nanotubes distribution types on the structural and acoustic response of laminated functionally graded carbon nanotube reinforced composite plates are also investigated.


2010 ◽  
Vol 10 (05) ◽  
pp. 1031-1053 ◽  
Author(s):  
S. PRADYUMNA ◽  
J. N. BANDYOPADHYAY

This paper investigates the free vibration and buckling behavior of singly and doubly curved shell panels made of functionally graded materials (FGMs). A higher-order shear deformation theory is used for the analysis of five shell panels, namely, cylindrical (CYL), spherical (SPH), hyperbolic paraboloid (HPR), hypar (HYP), and conoid (CON). The shell panels are subjected to a temperature field and in the case of buckling analysis, the shell panels are also subjected to a uniaxial compressive load. The properties of FGMs are considered to be temperature dependent and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. The accuracy of the formulation is validated by comparing the results with those available in the literature. The effects of geometric properties, material composition, and boundary conditions on the free vibration and buckling are studied.


2021 ◽  
Vol 59 (5) ◽  
Author(s):  
Thom Tran ◽  
Hien Thi Trinh ◽  
Kien Dinh Nguyen

This paper studies vibration of sandwich beams reinforced by carbon nanotubes (CNTs) under a moving point load. The core of the beams is homogeneous while their two faces are of carbon nanotube reinforced composite material. The effective properties of two face sheets are determined by extended rule of mixture.  A uniform distribution (UD) and four different types of functionally graded (FG) distributions, namely FG-X, FG-FG-V, FG-O, are considered. Based on a third-order shear deformation theory, a finite element formulation is derived and used to compute the vibration characteristics of the beams. 


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