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Showing papers on "Functionally graded material published in 2017"


Journal ArticleDOI
TL;DR: In this article, the authors explore the mechanical properties of functionally graded lattice structures fabricated by an additive manufacturing technique namely, selective laser melting (SLM), with Ti-6Al-4V as the building material.

280 citations


Journal ArticleDOI
TL;DR: In this article, the microstructure, composition, phases, and microhardness were determined as a function of position within a functionally graded materials (FGMs), and detrimental phases associated with the compositional blending of the Ti-6Al-4V and Invar formed, leading to cracking in the final part.

277 citations


Journal ArticleDOI
TL;DR: In this article, a study on the vibrations of functionally graded material (FGM) rectangular plates with porosities and moving in thermal environment was conducted, where the porosity distribution of the FGM plates was taken into account by using von Karman nonlinear plate theory.

216 citations


Journal ArticleDOI
12 Oct 2017
TL;DR: In this article, the authors present a state-of-the-art overview of the use of additive manufacturing (AM) technologies to produce orthopedic implants from lattice structures and functionally graded materials.
Abstract: A major advantage of additive manufacturing (AM) technologies is the ability to print customized products, which makes these technologies well suited for the orthopedic implants industry. Another advantage is the design freedom provided by AM technologies to enhance the performance of orthopedic implants. This paper presents a state-of-the-art overview of the use of AM technologies to produce orthopedic implants from lattice structures and functionally graded materials. It discusses how both techniques can improve the implants’ performance significantly, from a mechanical and biological point of view. The characterization of lattice structures and the most recent finite element analysis models are explored. Additionally, recent case studies that use functionally graded materials in biomedical implants are surveyed. Finally, this paper reviews the challenges faced by these two applications and suggests future research directions required to improve their use in orthopedic implants.

206 citations


Journal ArticleDOI
TL;DR: In this paper, a generalized shear deformation theory in combination with isogeometric (IGA) approach for nonlinear transient analysis of smart piezoelectric functionally graded material (FGM) plates is presented.
Abstract: We present a generalized shear deformation theory in combination with isogeometric (IGA) approach for nonlinear transient analysis of smart piezoelectric functionally graded material (FGM) plates. The nonlinear transient formulation for plates is formed in the total Lagrange approach based on the von Karman strains, which includes thermo-piezoelectric effects, and solved by Newmark time integration scheme. The electric potential through the thickness of each piezoelectric layer is assumed to be linear. The material properties vary through the thickness of FGM according to the rule of mixture and the Mori–Tanaka schemes. Various numerical examples are presented to demonstrate the effectiveness of the proposed method.

184 citations


Journal ArticleDOI
TL;DR: In this article, a size-dependent Euler-Bernoulli beam model is proposed to investigate the scaling effect on the post-buckling behaviors of functionally graded (FG) nanobeams with the von Karman geometric nonlinearity.

159 citations


Journal ArticleDOI
Ömer Civalek1
TL;DR: In this paper, free vibration analysis of conical and cylindrical shells and annular plates made of composite laminated and functionally graded materials (FGMs) is investigated for FGM cases.
Abstract: In this study, free vibration analysis of conical and cylindrical shells and annular plates made of composite laminated and functionally graded materials (FGMs) is investigated. Carbon nanotubes reinforced (CNTR) composite case is also taken consideration for FGM. The equations of motion for conical shell are obtained via Hamilton's principle using the transverse shear deformation theory. To obtain the eigenvalue problem of the system, the method of discrete singular convolution is employed. Material properties are graded in the thickness direction according to a volume fraction power law and four-parameter power law indexes for FGM cases. Five types of distributions of CNTR material are also considered. To verify the accuracy of this method, comparisons of the present results are made with results available in the open literature. Free vibrations of cylindrical shells and annular plates with FGM are treated as special cases. Results are also presented for carbon nanotubes reinforced (CNTR) composite cylindrical shells and annular plates. It is found that the convergence and accuracy of the present DSC method is very good for vibration problem of shells with functionally graded materials (FMG) and CNTR functionally graded materials.

158 citations


Journal ArticleDOI
TL;DR: In this article, the buckling characteristics of a curved functionally graded (FG) nanobeam based on nonlocal strain gradient elasticity theory accounting the stress for not only the nonlocal stress field but also the strain gradients stress field were investigated.

154 citations


Journal ArticleDOI
TL;DR: In this paper, a beam theory for bending, free vibration and buckling analysis of functionally graded material (FGM) beams on two-parameter elastic foundation is presented, which accounts for both shear deformation and thickness stretching effects by a parabolic variation of all displacements across the thickness, and satisfies the stress free boundary conditions on the upper and lower surfaces of the beam without requiring any shear correction factor.
Abstract: The novelty of this paper is the use of an efficient beam theory for bending, free vibration and buckling analysis of functionally graded material (FGM) beams on two-parameter elastic foundation. The present theory accounts for both shear deformation and thickness stretching effects by a parabolic variation of all displacements across the thickness, and satisfies the stress-free boundary conditions on the upper and lower surfaces of the beam without requiring any shear correction factor. Due to porosities, possibly occurring inside FGMs during fabrication, it is therefore necessary to consider the vibration, bending and buckling behaviors of beams having porosities in this work. The equation of motion for FGM beams is obtained through Hamilton’s principle. The closed form solutions are obtained by using Navier technique, and then fundamental frequencies are found by solving the results of eigenvalue problems. The validity of the present theory is investigated by comparing some of the present in literature. It can be concluded that the proposed theory is accurate and simple in solving the bending, free vibration and buckling behaviors of FGM sandwich beams.

148 citations


Journal ArticleDOI
TL;DR: In this paper, a suitable and simple computational formulation based on Isogeometric Analysis (IGA) integrated with higher-order shear deformation theory (HSDT) is introduced for size-dependent geometrically nonlinear transient analysis of functionally graded material (FGM) nanoplates.
Abstract: In the present investigation, a suitable and simple computational formulation based on Isogeometric Analysis (IGA) integrated with higher-order shear deformation theory (HSDT) is introduced for size-dependent geometrically nonlinear transient analysis of functionally graded material (FGM) nanoplates. The material properties of FGM based on the Mori–Tanaka schemes and the rule of mixture are used. The nonlinear transient nonlocal governing equations approximated according to IGA based on HSDT, which satisfies naturally the higher-order derivatives continuity requirement in weak form of the FGM nanoplates, are formed using the von Karman strains and solved by Newmark time integration scheme. The effect of nonlocal approach on the behaviors of the FGM nanoplates with several volume fraction exponents is investigated. Several numerical results are presented to demonstrate the reliability of the proposed method.

136 citations


Journal ArticleDOI
TL;DR: In this paper, the eigenvalue buckling of functionally graded graphene platelets (GPLs) reinforced cylindrical shells consisting of multiple layers through finite element method (FEM) was determined by modified Halpin-Tsai model and rule of mixture.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the nonlinear steady-state responses of longitudinally traveling functionally graded material (FGM) plates immersed in liquid for the first time, and the results showed strong hardening-type behavior of the system.

Journal ArticleDOI
TL;DR: In this paper, a transition composition route was introduced to avoid the intermetallic phases between Ti-6Al-4V and SS316, and a thin wall sample was fabricated via LMD.
Abstract: In this study, laser metal deposition (LMD) was employed to explore a new fabrication process for producing a functionally graded material (FGM) from Ti-6Al-4V to SS316. A transition composition route was introduced (Ti-6Al-4V→V→Cr→Fe→SS316) to avoid the intermetallic phases between Ti-6Al-4V and SS316. A thin wall sample was fabricated via LMD by following the transition composition route. Microstructure characterization and composition distribution analyses were performed by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The SEM images depicted the microstructural morphology of the FGM sample. The element gradient distribution determined by the EDS results may reflect the FGM transition composition route design. X-ray diffraction tests were conducted and the results demonstrated that the generation of intermetallic phases effectively avoided following the composition route. The Vickers hardness test was used to determine the Vickers hardness number (VHN) distribution from Ti-6Al-4V to SS316. The VHN results showed that no significant formation of hard brittle phases occurred in the LMD procedure.

Journal ArticleDOI
TL;DR: In this paper, the free vibration analysis of a functionally graded (FG) porous cylindrical microshell subjected to a thermal environment is investigated on the basis of the first-order shear deformation shells and the modified couple stress theories.
Abstract: In this article, the free vibration analysis of a functionally graded (FG) porous cylindrical microshell subjected to a thermal environment is investigated on the basis of the first-order shear deformation shells and the modified couple stress theories. The material properties are assumed to be temperature dependent and are graded in the thickness direction. The equations of motion and the related boundary conditions are derived using the principle of minimum potential energy and they are solved analytically. The model is validated by comparing the benchmark results with the obtained ones. The effects of material length scale parameter, temperature changes, volume fraction of the porosity, FG power index, axial and circumferential wave number, and length on the vibration behavior of the FG porous cylindrical microshell are studied. The results can have many applications such as in modeling of microrobots and biomedical microsystems.

Journal ArticleDOI
TL;DR: In this article, a nonlocal integral model is formulated to investigate the twisting static behaviors of through-radius functionally graded (FG) nanotubes based on Eringen's non-local integral elasticity.

Journal ArticleDOI
TL;DR: In this paper, the D'Alembert's principle is used to discretize the governing equation to a system of ordinary differential equations and the method of harmonic balance is adopted to perform an approximately analytical analysis on the present model.
Abstract: Vibrations of longitudinally traveling functionally graded material (FGM) plates with porosities are studied for the first time. The FGM plates contain porosities owing to the technical issues during the preparation of FGMs. Two different porosity distributions, namely, even and uneven distribution, are considered in this paper. The large-amplitude motion of FGM plates is taken into account so that the present model includes both geometry and material nonlinearities. The governing equation of the present system is derived by using the D'Alembert's principle. The Galerkin method is utilized to discretize the governing equation to a system of ordinary differential equations. The method of harmonic balance is adopted to perform an approximately analytical analysis on the present model. Then the analytical results are validated by the comparison with numerical solutions, which are obtained by using the adaptive step-size fourth-order Runge-Kutta method. Moreover, the stability of steady-state analytical solutions is analyzed. Nonlinear vibrational responses for both FGM plates with evenly distributed porosities (EDP) and unevenly distributed porosities (UEDP) are examined. A 1:1 internal resonance behavior is discovered and it is found that this behavior can be excited by very small external excitation. Furthermore, the effects of porosity volume fraction, damping and constituent volume fraction on the dynamic response of the system are highlighted.

Journal ArticleDOI
TL;DR: In this article, the generalized Mian and Spencer method is utilized to obtain the analytical solutions of nanocomposite rectangular plate with two opposite edges simply supported and under a uniformly distributed transverse load and a temperature change.
Abstract: Thermoelastic bending behaviour of novel functionally graded polymer nanocomposite rectangular plate reinforced with graphene nanoplatelets (GPLs) whose weight fraction varies continuously and smoothly along the thickness direction is investigated. The generalized Mian and Spencer method is utilized to obtain the analytical solutions of nanocomposite rectangular plate with two opposite edges simply supported and under a uniformly distributed transverse load and a temperature change. Three GPL distribution patterns are considered. Comparison between the present analytical solutions and those available in literature is carried out to verify the accuracy of our analytical solutions. A parametric study is conducted to examine the effects of GPL’s weight fraction, distribution pattern, geometry and size as well as the temperature change and plate boundary conditions on the stress and deformation fields of the nanocomposite plates. Numerical results show that the addition of GPLs at a very low content can have a significant reinforcing effect on the thermo-mechanical response of the plate.

Journal ArticleDOI
TL;DR: In this article, a micromechanical approach is used to estimate the thermomechanical properties of the composite media and a non-uniform rational B-spline (NURBS) based isogeometric finite element method was used to study the thermal buckling response of the graphene reinforced composite plates.

Journal ArticleDOI
TL;DR: In this article, a multi-layered shell formulation is developed based on a layerwise deformation theory within the framework of isogeometric analysis (IGA), which utilizes Non-Uniform Rational B-splines (NURBS) to represent the geometry as well as to describe the field variables.

Journal ArticleDOI
TL;DR: In this paper, a finite element formulation of a coupled thermo-mechanical problem in functionally graded metal/ceramic plates is presented, which is applied to the development of a functionally graded two-dimensional plane strain finite element.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed an efficient numerical mesh-free approach to analyze static bending and free vibration of functionally graded (FG) plates. And the kinematics of plates are based on a simple first-order shear deformation theory (FSDT), which is an effective four-variable refined plate theory.
Abstract: Modeling of mechanical behavior of plates has been accomplished in the past decades, with different numerical strategies including the finite element and meshfree methods, and with a range of plate theories including the first-order shear deformation theory (FSDT). In this paper, we propose an efficient numerical meshfree approach to analyze static bending and free vibration of functionally graded (FG) plates. The kinematics of plates is based on a novel simple FSDT, termed as S-FSDT, which is an effective four-variable refined plate theory. The S-FSDT requires C 1 -continuity that is satisfied with the basis functions based on moving Kriging interpolation. Some major features of the approach can be summarized: (a) it is less computationally expensive due to having fewer unknowns; (b) it is naturally free from shear-locking; (c) it captures the physics of shear-deformation effect present in the conventional FSDT; (d) the essential boundary conditions can straightforwardly be treated, the same as the FEM; and (e) it can deal with both thin and thick plates. All these features will be demonstrated through numerical examples, which are to confirm the accuracy and effectiveness of the proposed method. Additionally, a discussion on other possible choices of correlation functions used in the model is given.

Journal ArticleDOI
TL;DR: In this paper, the free vibration behavior of carbon nanotube (CNT) reinforced functionally graded thick laminated composite plates utilizing Reddy's higher-order shear deformation theory (HSDT) is studied.

Journal ArticleDOI
TL;DR: In this paper, the large-amplitude vibration of sigmoid functionally graded material (S-FGM) thin plates with porosities was investigated by applying the von Karman non-linear plate theory.
Abstract: This research focuses on the large-amplitude vibration of sigmoid functionally graded material (S-FGM) thin plates with porosities. Porosities in S-FGM plates can happen due to technical issues during the preparation of S-FGMs. Two types of porosity distribution, i.e., even and uneven distribution, are taken into account. The material properties of S-FGM plates with porosities change smoothly along the thickness direction based on the sigmoid distribution law, which is described by modified piecewise functions. The geometrical nonlinearity is considered by applying the von Karman non-linear plate theory. The nonlinear governing equation of S-FGM plates with porosities is derived using the D′Alembert's principle. By applying the Galerkin method with the first three modes, the governing equation is discretized to three ordinary differential equations. Then, the method of harmonic balance is used to solve these discretized equations. Analytical results are verified numerically with the adaptive step-size fourth-order Runge-Kutta method. The stability of the steady-state response is examined by means of the perturbation technique. Furthermore, the maximum amplitudes of each mode during the vibration period are obtained and shown in the neighborhood of the fundamental mode. Study demonstrates that the S-FGM plates with porosities possess hardening spring characteristics in nonlinear frequency response. Moreover, a complex multi-solution phenomenon occurs in the present dynamic system which is rooted from the nonlinear mode interaction. Finally, investigation is made on the effects of porosity along with other key parameters on large-amplitude vibration response of porous S-FGM plates.

Journal ArticleDOI
TL;DR: In this paper, the static bending and forced vibration of an imperfect FG microplate carrying a moving load are dealt with based on Mindlin plate theory (MPT) and the modified couple stress theory (MCST).

Journal ArticleDOI
TL;DR: In this article, the free vibration analysis of edge cracked cantilever microscale beams composed of functionally graded material (FGM) is investigated based on the modified couple stress theory (MCST), where the material properties of the beam are assumed to change in the height direction according to the exponential distribution.
Abstract: In this study, the free vibration analysis of edge cracked cantilever microscale beams composed of functionally graded material (FGM) is investigated based on the modified couple stress theory (MCST). The material properties of the beam are assumed to change in the height direction according to the exponential distribution. The cracked beam is modeled as a modification of the classical cracked-beam theory consisting of two sub-beams connected by a massless elastic rotational spring. The inclusion of an additional material parameter enables the new beam model to capture the size effect. The new nonclassical beam model reduces to the classical one when the length scale parameter is zero. The problem considered is investigated using the Euler–Bernoulli beam theory by the finite element method. The system of equations of motion is derived by Lagrange’s equations. To verify the accuracy of the present formulation and results, the frequencies obtained are compared with the results available in the literature, for which good agreement is observed. Numerical results are presented to investigate the effect of crack position, beam length, length scale parameter, crack depth, and material distribution on the natural frequencies of the edge cracked FG microbeam. Also, the difference between the classical beam theory (CBT) and MCST is investigated for the vibration characteristics of the beam of concern. It is believed that the results obtained herein serve as a useful reference for research of similar nature.

Journal ArticleDOI
TL;DR: In this paper, a three-dimensional analysis of a multi-directional skew plate on elastic foundation under thermo-mechanical loading is carried out for the first time, and the results show that the material grading direction has a noticeable effect on plate behavior especially for the plates under thermal loading as well as for the dynamic response of the plate.
Abstract: Three-dimensional thermo-elastic analysis of a multi-directional functionally graded skew plate on elastic foundation under thermo-mechanical loading is carried out for the first time. Numerical results of displacement and stresses are obtained using differential quadrature method (DQM). Some material properties of the plate assumed to be temperature-dependent and graded in all three spatial directions according to a power law function. The results for various boundary conditions are obtained and the effects of grading index of material properties, temperature distribution, elastic foundation parameters and angle of skew plate are presented. Moreover, the dynamic response of a multi-directional functionally graded material skew plate on elastic foundation is obtained using 4D DQM for the first time. The results show that the material grading direction has a noticeable effect on plate behavior especially for the plates under thermal loading as well as for the dynamic response of the plate.

Journal ArticleDOI
TL;DR: In this paper, a hybrid method which combines reverberation-ray matrix method and wave propagation method is developed to investigate the stability of multi-span viscoelastic functionally graded material (FGM) pipes conveying fluid.
Abstract: In this paper, a hybrid method which combines reverberation-ray matrix method and wave propagation method is developed to investigate the stability of multi-span viscoelastic functionally graded material (FGM) pipes conveying fluid. The material properties of FGM pipes are considered as graded distribution along thickness direction according to a power-law. A parametric study is conducted to verify the effectiveness of present method and investigate effects of volume fraction exponent, fluid velocity, internal pressure and internal damping on stability of the FGM pipes conveying fluid. The numerical results demonstrate that the present method provides accurate results by using only a small number of elements and the viscoelastic FGM pipes exhibit some special dynamic behaviors. Moreover, the results also reveal that the natural frequencies of FGM piping system could be adjusted by devising the volume fraction exponent. This particular feature of FGM pipes can be tailored to fulfill the special applications in engineering.

Journal ArticleDOI
TL;DR: In this article, a finite element formulation based on a higher-order layerwise theory is presented for the first time to investigate thermally induced vibrations of functionally graded material (FGM) sandwich plates and shell panels.

Journal ArticleDOI
TL;DR: In this paper, the size-dependent buckling and postbuckling responses of hybrid functionally graded nanoshells integrated with surface-bonded piezoelectric nanolayers are studied in the presence of initial geometric imperfection.

Journal ArticleDOI
TL;DR: In this article, an efficient and simple refined theory is proposed for buckling analysis of functionally graded plates by using a new displacement field which includes undetermined integral variables, with is even less than the first shear deformation theory (FSDT).
Abstract: In this article, an efficient and simple refined theory is proposed for buckling analysis of functionally graded plates by using a new displacement field which includes undetermined integral variables. This theory contains only four unknowns, with is even less than the first shear deformation theory (FSDT). Governing equations are obtained from the principle of virtual works. The closed-form solutions of rectangular plates are determined. Comparison studies are carried out to check the validity of obtained results. The influences of loading conditions and variations of power of functionally graded material, modulus ratio, aspect ratio, and thickness ratio on the critical buckling load of functionally graded plates are examined and discussed.