• Title, Summary, Keyword: Functionally Graded Material

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Interfacial stresses in RC beam bonded with a functionally graded material plate

  • Daouadji, Tahar Hassaine;Chedad, Abdebasset;Adim, Belkacem
    • Structural Engineering and Mechanics
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    • v.60 no.4
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    • pp.693-705
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    • 2016
  • Functionally graded material (FGM) plates can be bonded to the soffit of a beam as a means of retrofitting the RC beam. In such plated beams, tensile forces develop in the bonded plate and these have to be transferred to the original beam via interfacial shear and normal stresses. In this paper, an interfacial stress analysis is presented for simply supported concrete beam bonded with a functionally graded material FGM plate. This new solution is intended for application to beams made of all kinds of materials bonded with a thin plate, while all existing solutions have been developed focusing on the strengthening of reinforced concrete beams, which allowed the omission of certain terms. It is shown that both the normal and shear stresses at the interface are influenced by the material and geometry parameters of the composite beam. This research is helpful for the understanding on mechanical behavior of the interface and design of the FGM-RC hybrid structures.

Effects of temperature dependent material properties on mixed mode crack tip parameters of functionally graded materials

  • Rajabi, Mohammad;Soltani, Nasser;Eshraghi, Iman
    • Structural Engineering and Mechanics
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    • v.58 no.2
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    • pp.217-230
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    • 2016
  • Effects of temperature dependent material properties on mixed mode fracture parameters of functionally graded materials subjected to thermal loading are investigated. A domain form of the $J_k$-integral method including temperature-dependent material properties and its numerical implementation using finite element analysis is presented. Temperature and displacement fields are calculated using finite element analysis and are used to compute mixed mode stress intensity factors using the $J_k$-integral. Numerical results indicate that temperature-dependency of material properties has considerable effect on the mixed-mode stress intensity factors of cracked functionally graded structures.

Finite Element Analysis of Functionally Graded Plates using Inverse Hyperbolic Shear Deformation Theory

  • Kulkarni, Kamlesh;Singh, Bhrigu Nath;Maiti, Dipak Kumar
    • International Journal of Aerospace System Engineering
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    • v.3 no.1
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    • pp.1-4
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    • 2016
  • Functionally graded materials (FGMs) are becoming very popular in various industries due to their effectiveness of the utilization of their constituent elements. However, the modelling of these materials is difficult due to the complex nature of variation of material properties across the thickness. Many shear deformation theories have been developed and employed for the analysis of such functionally graded plates (FGPs). A recently developed inverse hyperbolic shear deformation theory has been successfully employed by Grover et al. [1] for the analysis of laminated composites and sandwich plates. The objective of the study is to obtain finite element solution for the structural analysis of functionally graded plates using inverse hyperbolic shear deformation theory. Finite element analysis facilitates the analysis of complex problems such as functionally graded plates with different boundary conditions and different loadings.

Transient Response of Functionally Graded Piezoelectric Ceramic with Crack (균열이 있는 기능경사 압전 세라믹의 충격 특성에 관한 연구)

  • Jeong Woo Shin;Tae-Uk Kim;Sung Chan Kim
    • Composites Research
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    • v.16 no.5
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    • pp.21-27
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    • 2003
  • Using the theory of linear piezoelectricity, the dynamic response of a central crack in a functionally graded piezoelectric ceramic under anti-plane shear impact is analyzed. We assume that the properties of the functionally graded piezoelectric material vary continuously along the thickness. By using the Laplace and Fourier transform, the problem is reduced to two pairs of dual integral equations and then into Fredholm integral equations of the second kind. Numerical values on the dynamic stress intensity factors are presented to show the dependence of the gradient of material properties and electric loading.

Assessment of new 2D and quasi-3D nonlocal theories for free vibration analysis of size-dependent functionally graded (FG) nanoplates

  • Bendaho, Boudjema;Belabed, Zakaria;Bourada, Mohamed;Benatta, Mohamed Atif;Bourada, Fouad;Tounsi, Abdelouahed
    • Advances in nano research
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    • v.7 no.4
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    • pp.277-292
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    • 2019
  • In this present paper, a new two dimensional (2D) and quasi three dimensional (quasi-3D) nonlocal shear deformation theories are formulated for free vibration analysis of size-dependent functionally graded (FG) nanoplates. The developed theories is based on new description of displacement field which includes undetermined integral terms, the issues in using this new proposition are to reduce the number of unknowns and governing equations and exploring the effects of both thickness stretching and size-dependency on free vibration analysis of functionally graded (FG) nanoplates. The nonlocal elasticity theory of Eringen is adopted to study the size effects of FG nanoplates. Governing equations are derived from Hamilton's principle. By using Navier's method, analytical solutions for free vibration analysis are obtained through the results of eigenvalue problem. Several numerical examples are presented and compared with those predicted by other theories, to demonstrate the accuracy and efficiency of developed theories and to investigate the size effects on predicting fundamental frequencies of size-dependent functionally graded (FG) nanoplates.

A sinusoidal plate theory with 5-unknowns and stretching effect for thermomechanical bending of functionally graded sandwich plates

  • Hamidi, Ahmed;Houari, Mohammed Sid Ahmed;Mahmoud, S.R.;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.18 no.1
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    • pp.235-253
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    • 2015
  • In this research, a simple but accurate sinusoidal plate theory for the thermomechanical bending analysis of functionally graded sandwich plates is presented. The main advantage of this approach is that, in addition to incorporating the thickness stretching effect, it deals with only 5 unknowns as the first order shear deformation theory (FSDT), instead of 6 as in the well-known conventional sinusoidal plate theory (SPT). The material properties of the sandwich plate faces are assumed to vary according to a power law distribution in terms of the volume fractions of the constituents. The core layer is made of an isotropic ceramic material. Comparison studies are performed to check the validity of the present results from which it can be concluded that the proposed theory is accurate and efficient in predicting the thermomechanical behavior of functionally graded sandwich plates. The effect of side-to-thickness ratio, aspect ratio, the volume fraction exponent, and the loading conditions on the thermomechanical response of functionally graded sandwich plates is also investigated and discussed.

Thermal Characteristic Evaluation of Functionally Graded Composites for PSZ/Metal

  • Lim, Jae-Kyoo;Song, Jun-Hee
    • Journal of Mechanical Science and Technology
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    • v.14 no.3
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    • pp.298-305
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    • 2000
  • The functionally graded material (FGM) is the new concept for a heat resisting material. FGM consists of ceramics on one side and metal on the other. A composition and microstructure of an intermediate layer change continuously from ceramics to metal at the micron level. This study is carried out to analyze the thermal shock characteristics of functionally graded PSZ/ metal composites. Heat-resistant property was evaluated by gas burner heating test using $C_2H_2/O_2$ combustion flame. The ceramic surface was heated with burner flame and the bottom surface cooled with water flow. Also, the composition profile and the thickness of the graded layer were varied to study the thermo mechanical response. Furthermore, this study carried out the thermal stress analysis to investigate the thermal characteristics by the finite element method. Acoustic emission (AE) monitoring was performed to detect the microfracture process in a thermal shock test.

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Nonlinear cylindrical bending of functionally graded carbon nanotube-reinforced composite plates

  • Kaci, Abdelhakim;Tounsi, Abdelouahed;Bakhti, Karima;Adda Bedia, El Abbas
    • Steel and Composite Structures
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    • v.12 no.6
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    • pp.491-504
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    • 2012
  • In this paper, the nonlinear cylindrical bending of simply supported, functionally graded nanocomposite plates reinforced by single-walled carbon nanotubes (SWCNTs), is studied. The plates are subjected to uniform pressure loading in thermal environments and their geometric nonlinearity is introduced in the strain-displacement equations based on Von-Karman assumptions. The material properties of SWCNTs are assumed to be temperature-dependent and are obtained from molecular dynamics simulations. The material properties of functionally graded carbon nanotube-reinforced composites (FG-CNTCRs) are assumed to be graded in the thickness direction, and are estimated through a micromechanical model. The governing equations are reduced to linear differential equation with nonlinear boundary conditions yielding a simple solution procedure. Numerical results are presented to show the effect of the material distribution on the deflections and stresses.

Dynamic instability of functionally graded material plates subjected to aero-thermo-mechanical loads

  • Prakash, T.;Ganapathi, M.
    • Structural Engineering and Mechanics
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    • v.20 no.4
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    • pp.435-450
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    • 2005
  • Here, the dynamic instability characteristics of aero-thermo-mechanically stressed functionally graded plates are investigated using finite element procedure. Temperature field is assumed to be a uniform distribution over the plate surface and varied in thickness direction only. Material properties are assumed to be temperature dependent and graded in the thickness direction according to simple power law distribution. For the numerical illustrations, silicon nitride/stainless steel is considered as functionally graded material. The aerodynamic pressure is evaluated based on first-order high Mach number approximation to the linear potential flow theory. The boundaries of the instability region are obtained using the principle of Bolotin's method and are conveniently represented in the non-dimensional excitation frequency-load amplitude plane. The variation dynamic instability width is highlighted considering various parameters such as gradient index, temperature, aerodynamic and mechanical loads, thickness and aspect ratios, and boundary condition.

A new higher-order shear and normal deformation theory for functionally graded sandwich beams

  • Bennai, Riadh;Atmane, Hassen Ait;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.19 no.3
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    • pp.521-546
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    • 2015
  • A new refined hyperbolic shear and normal deformation beam theory is developed to study the free vibration and buckling of functionally graded (FG) sandwich beams under various boundary conditions. The effects of transverse shear strains as well as the transverse normal strain are taken into account. Material properties of the sandwich beam faces 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. The core layer is still homogeneous and made of an isotropic material. Equations of motion are derived from Hamilton's principle. Analytical solutions for the bending, free vibration and buckling analyses are obtained for simply supported sandwich beams. Illustrative examples are given to show the effects of varying gradients, thickness stretching, boundary conditions, and thickness to length ratios on the bending, free vibration and buckling of functionally graded sandwich beams.