• Title/Summary/Keyword: Shear Deformation

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Bending of FGM rectangular plates resting on non-uniform elastic foundations in thermal environment using an accurate theory

  • Bouderba, Bachir
    • Steel and Composite Structures
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    • v.27 no.3
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    • pp.311-325
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    • 2018
  • This article presents the bending analysis of FGM rectangular plates resting on non-uniform elastic foundations in thermal environment. Theoretical formulations are based on a recently developed refined shear deformation theory. The displacement field of the present theory is chosen based on nonlinear variations in the in-plane displacements through the thickness of the plate. The present theory satisfies the free transverse shear stress conditions on the top and bottom surfaces of the plate without using shear correction factor. Unlike the conventional trigonometric shear deformation theory, the present refined shear deformation theory contains only four unknowns as against five in case of other shear deformation theories. The material properties of the functionally graded plates are assumed to vary continuously through the thickness, according to a simple power law distribution of the volume fraction of the constituents. The elastic foundation is modeled as non-uniform foundation. The results of the shear deformation theories are compared together. Numerical examples cover the effects of the gradient index, plate aspect ratio, side-to-thickness ratio and elastic foundation parameters on the thermo-mechanical behavior of functionally graded plates. Numerical results show that the present theory can archive accuracy comparable to the existing higher order shear deformation theories that contain more number of unknowns.

A novel shear and normal deformation theory for hygrothermal bending response of FGM sandwich plates on Pasternak elastic foundation

  • Abazid, Mohammad Alakel;Alotebi, Muneerah S.;Sobhy, Mohammed
    • Structural Engineering and Mechanics
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    • v.67 no.3
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    • pp.219-232
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    • 2018
  • This paper deals with the static bending of various types of FGM sandwich plates resting on two-parameter elastic foundations in hygrothermal environment. The elastic foundation is modeled as Pasternak's type, which can be either isotropic or orthotropic and as a special case, it converges to Winkler's foundation if the shear layer is neglected. The present FGM sandwich plate is assumed to be made of a fully ceramic core layer sandwiched by metal/ceramic FGM coats. The governing equations are derived from principle of virtual displacements based on a shear and normal deformations plate theory. The present theory takes into account both shear and normal strains effects, thus it predicts results more accurate than the shear deformation plate theories. The results obtained by the shear and normal deformation theory are compared with those available in the literature and also with those obtained by other shear deformation theories. It is concluded that the present results are slightly deviated from other results because the normal deformation effect is taken into account. Numerical results are presented to show the effects of the different parameters, such as side-to-thickness ratio, foundation parameters, aspect ratio, temperature, moisture, power law index and core thickness on the stresses and displacements of the FG sandwich plates.

New Deformation Mechanism in the Forming of Cones by Shear Spinning (전단 스피닝에 의한 원추형상의 성형에 관한 변형 메커니즘)

  • Kim J. H.;Kim Chul
    • Transactions of Materials Processing
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    • v.14 no.4 s.76
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    • pp.375-383
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    • 2005
  • The shear spinning process, where the plastic deformation zone is localized in a very small portion of the workpiece, shows a promise for increasingly broader application to the production of axially symmetric parts. In this paper, the three components of the working force are calculated by a newly proposed deformation model in which the spinning process is understood as shearing deformation after uniaxial yielding by bending, and shear stress, $\tau_{rz}$, becomes k, yield limit in pure shear, in the deformation zone. The tangential force are first calculated and the feed force and the normal force are obtained by the assumption of uniform distribution of roller pressure on the contact surface. The optimum contact area is obtained by minimizing the bending energy required to get the assumed deformation of the blank. The calculated forces are compared with experimental results. A comparison shows that theoretical prediction is reasonably in good agreement with experimental results

A higher order shear deformation theory for static and free vibration of FGM beam

  • Hadji, L.;Daouadji, T.H.;Tounsi, A.;Bedia, E.A.
    • Steel and Composite Structures
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    • v.16 no.5
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    • pp.507-519
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    • 2014
  • In this paper, a higher order shear deformation beam theory is developed for static and free vibration analysis of functionally graded beams. The theory account for higher-order variation of transverse shear strain through the depth of the beam and satisfies the zero traction boundary conditions on the surfaces of the beam without using shear correction factors. The material properties of the functionally graded beam are assumed to vary according to power law distribution of the volume fraction of the constituents. Based on the present higher-order shear deformation beam theory, the equations of motion are derived from Hamilton's principle. Navier type solution method was used to obtain frequencies. Different higher order shear deformation theories and classical beam theories were used in the analysis. A static and free vibration frequency is given for different material properties. The accuracy of the present solutions is verified by comparing the obtained results with the existing solutions.

Stability and vibration analysis of composite plates using spline finite strips with higher-order shear deformation

  • Akhras, G.;Li, W.
    • Structural Engineering and Mechanics
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    • v.27 no.1
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    • pp.1-16
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    • 2007
  • In the present study, a spline finite strip with higher-order shear deformation is formulated for the stability and free vibration analysis of composite plates. The analysis is conducted based on Reddy's third-order shear deformation theory, Touratier's "Sine" model, Afaq's exponential model and Cho's higher-order zigzag laminate theory. Consequently, the shear correction coefficients are not required in the analysis, and an improved accuracy for thick laminates is achieved. The numerical results, based on different shear deformation theories, are presented in comparison with the three-dimensional elasticity solutions. The effects of length-to-thickness ratio, fibre orientation, and boundary conditions on the critical buckling loads and natural frequencies are investigated through numerical examples.

Bending response of functionally graded piezoelectric plates using a two-variable shear deformation theory

  • Zenkour, Ashraf M.;Hafed, Zahra S.
    • Advances in aircraft and spacecraft science
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    • v.7 no.2
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    • pp.115-134
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    • 2020
  • This paper proposes a bending analysis for a functionally graded piezoelectric (FGP) plate through utilizing a two-variable shear deformation plate theory under simply-supported edge conditions. The number of unknown functions used in this theory is only four. The electric potential distribution is assumed to be a combination of a cosine function along the cartesian coordinate. Applying the analytical solutions of FGP plate by using Navier's approach and the principle of virtual work, the equilibrium equations are derived. The paper also discusses thoroughly the impact of applied electric voltage, plate's aspect ratio, thickness ratio and inhomogeneity parameter. Results are compared with the analytical solution obtained by classical plate theory, first-order-shear deformation theory, higher-order shear deformation plate theories and quasi-three-dimensional sinusoidal shear deformation plate theory.

Cylindrical bending of multilayered composite laminates and sandwiches

  • Sayyad, Atteshamuddin S.;Ghugal, Yuwaraj M.
    • Advances in aircraft and spacecraft science
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    • v.3 no.2
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    • pp.113-148
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    • 2016
  • In a whole variety of higher order plate theories existing in the literature no consideration is given to the transverse normal strain / deformation effects on flexural response when these higher order theories are applied to shear flexible composite plates in view of minimizing the number of unknown variables. The objective of this study is to carry out cylindrical bending of simply supported laminated composite and sandwich plates using sinusoidal shear and normal deformation plate theory. The most important feature of the present theory is that it includes the effects of transverse normal strain/deformation. The displacement field of the presented theory is built upon classical plate theory and uses sine and cosine functions in terms of thickness coordinate to include the effects of shear deformation and transverse normal strain. The theory accounts for realistic variation of the transverse shear stress through the thickness and satisfies the shear stress free conditions at the top and bottom surfaces of the plate without using the problem dependent shear correction factor. Governing equations and boundary conditions of the theory are obtained using the principle of minimum potential energy. The accuracy of the proposed theory is examined for several configurations of laminates under various static loadings. Some problems are presented for the first time in this paper which can become the base for future research. For the comparison purpose, the numerical results are also generated by using higher order shear deformation theory of Reddy, first-order shear deformation plate theory of Mindlin and classical plate theory. The numerical results show that the present theory provides displacements and stresses very accurately as compared to those obtained by using other theories.

Transfer Length of the Soil Nail Induced by the Shear Deformation (전단변형에 따른 쏘일네일의 전이길이)

  • You, Min Ku;Lee, Sang Duk
    • Journal of the Korean Geotechnical Society
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    • v.34 no.6
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    • pp.61-73
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    • 2018
  • When the shear deformation occurs on the slope reinforced with soil nail, a passive earth pressure is induced on the ground around the soil nail and the increase of shear deformation causes the earth pressure variation of the ground and the deformation and member force change of the soil nail. In this study, the shear behavior of the soil nail was analyzed experimentally by inducing the shear deformation in the vertical direction of the soil nail using a large-scale direct shear test equipment and it was verified through numerical analysis. The shear test was performed on the bonded length (6D, 8D, 10D and 12D) of the soil nail separated from the shear surface. As a result, it was observed that the continuous increase of the shear deformation caused the damage of the grout and the effect according to the bonded length was analyzed. Through the model test and the numerical analysis, it was confirmed that the transfer length of the soil nail was 0.2~0.22m, which is larger than 0.1m suggested in the previous study, and the shear zone was in the range of 0.6m from the shear surface.

Comparison of Various Shear Deformation Functions for Laminated Composite/Sandwich Plates (복합적층 및 샌드위치판 전단변형함수에 관한 상호비교연구)

  • Park, Won-Tae;Chang, Suk-Yoon;Chun, Kyoung-Sik
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.1 no.3
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    • pp.1-9
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    • 2010
  • In this paper, we used various shear deformation functions for modelling isotropic, symmetric composite and sandwich plates discretized by a mixed finite element method based on the Lagrangian/Hermite interpolation functions. These shear deformation theories uses polynomial, trigonometric, hyperbolic and exponential functions through the thickness direction, allowing for zero transverse shear stresses at the top and bottom surfaces of the plate. All shear deformation functions are compared with other available analytical/3D elasticity solutions, are predicted the reasonable accuracy for investigated problems. Particularly, The present results show that the use of exponential shear deformation theory (Karama et al. 2003; Aydogu 2009) provides very good solutions for composite and sandwich plates.

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Bending Assessment of Antisymmetric Angle-ply Composite Sandwich Plates with Various Shear Deformation Functions (전단변형함수에 따른 역대칭 앵글-플라이 복합면재를 갖는 샌드위치판의 휨거동 평가)

  • Park, Weon-Tae;Chun, Kyoung-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.11
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    • pp.5347-5356
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    • 2011
  • In this paper, we compared various shear deformation functions for modelling anti-symmetric composite sandwich plates discretized by a mixed finite element method based on the Lagrangian/Hermite interpolation functions. These shear deformation theories uses polynomial, trigonometric, hyperbolic and exponential functions through the thickness direction, allowing for zero transverse shear stresses at the top and bottom surfaces of the plate. All shear deformation functions are compared with other available analytical/3D elasticity solutions, As a result, reasonable accuracy for investigated problems are predicted. Particularly, The present results show that the use of exponential shear deformation theory provides very good solutions for composite sandwich plates.