• Title/Summary/Keyword: buckling sandwich plates

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Vibration and stability of initially stressed sandwich plates with FGM face sheets in thermal environments

  • Chen, Chun-Sheng;Liu, Fwu-Hsing;Chen, Wei-Ren
    • Steel and Composite Structures
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    • v.23 no.3
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    • pp.251-261
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    • 2017
  • In this paper, thermal effect on the vibration and stability of initially stressed sandwich plates with functionally graded material (FGM) face sheets is analyzed. Material properties of FGM face sheet are graded continuously in the thickness direction. The variation of FGM properties assumes a simple power law distribution in terms of the volume fractions of the constituents. The governing equations of arbitrarily initially-stressed sandwich plates including the effects of transverse shear deformation and rotary inertia are derived. The initial stress is taken to be a combination of a uniaxial extensional stress and a pure bending stress in the examples. The eigenvalue problems are formed to study the vibration and buckling characteristics of simple supported initially stressed FGM/metal/FGM plates. The effects of volume fraction index, temperature rise, initial stress and layer thickness of metal on the natural frequencies and buckling loads are investigated. The results reveal that the volume fraction index, initial stresses and layer thickness of metal have significant influence on the vibration and stability of sandwich plates with FGM face sheets.

Buckling Analysis of Sandwich Plate with Thin Faces (얇은 면재를 갖는 샌드위치 평판의 좌굴강도 해석)

  • H.K. Yang;J.W. Lee;Y.H. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.32 no.4
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    • pp.87-96
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    • 1995
  • This study is concerned with the overall buckling analysis of sandwich plates under biaxial loads by applying the Rayleigh-Ritz method, which are considered to buckle simultaneously in overall from of core and thin faces together. In order to study the effects of boundary conditions on the buckling behaviors, the simply supported, flexed and it's combined boundary conditions are considered as well as the effects of material characteristics of core and thin faces of sandwich plates on the buckling behaviors.

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Optimal Design of Metallic Sandwich Plates with Inner Dimpled Shell Subjected to 3-Point Bending (굽힘 하중을 받는 딤플형 금속 샌드위치판재의 최적설계)

  • Seong D.Y.;Jung C.G.;Yoon S.J.;Yang D.Y.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.702-705
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    • 2005
  • Metallic sandwich plates with Inner dimpled shell subjected to 3-point bending have been analyzed and then optimized for minimum weight. Inner dimpled shells can be easily fabricated by press or roll with high quality precision and bonded with same material skin sheets by resistance welding or adhesive bonding process. Optimized shape of inner dimple is a hemispherical shell to minimize weight without failure, including face yielding, face buckling and inner dimple buckling. It is demonstrated that bending stiffness of sandwich plate is 2 or 3 times than solid plates with same strength

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Investigation of thermal buckling properties of ceramic-metal FGM sandwich plates using 2D integral plate model

  • Salah, Fethi;Boucham, Belhadj;Bourada, Fouad;Benzair, Abdelnour;Bousahla, Abdelmoumen Anis;Tounsi, Abdeldjebbar
    • Steel and Composite Structures
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    • v.33 no.6
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    • pp.805-822
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    • 2019
  • In this work, a simple four-variable integral plate theory is employed for examining the thermal buckling properties of functionally graded material (FGM) sandwich plates. The proposed kinematics considers integral terms which include the effect of transverse shear deformations. Material characteristics and thermal expansion coefficient of the ceramic-metal FGM sandwich plate faces are supposed to be graded in the thickness direction according to a "simple power-law" variation in terms of the "volume fractions" of the constituents. The central layer is always homogeneous and consists of an isotropic material. The thermal loads are supposed as uniform, linear, and nonlinear temperature rises within the thickness direction. The influences of geometric ratios, gradient index, loading type, and type sandwich plate on the buckling properties are examined and discussed in detail.

Nonlocal strain gradient theory for buckling and bending of FG-GRNC laminated sandwich plates

  • Basha, Muhammad;Daikh, Ahmed Amine;Melaibari, Ammar;Wagih, Ahmed;Othman, Ramzi;Almitani, Khalid H;Hamed, Mostafa A.;Abdelrahman, Alaa;Eltaher, Mohamed A.
    • Steel and Composite Structures
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    • v.43 no.5
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    • pp.639-660
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    • 2022
  • The bending and buckling behaviours of FG-GRNC laminated sandwich plates are investigated by using novel five-variables quasi 3D higher order shear deformation plate theory by considering the modified continuum nonlocal strain gradient theory. To calculate the effective Young's modulus of the GRNC sandwich plate along the thickness direction, and Poisson's ratio and mass density, the modified Halpin-Tsai model and the rule of the mixture are employed. Based on a new field of displacement, governing equilibrium equations of the GRNC sandwich plate are solved using a developed approach of Galerkin method. A detailed parametric analysis is carried out to highlight the influences of length scale and material scale parameters, GPLs distribution pattern, the weight fraction of GPLs, geometry and size of GPLs, the geometry of the sandwich plate and the total number of layers on the stresses, deformation and critical buckling loads. Some details are studied exclusively for the first time, such as stresses and the nonlocality effect.

Local buckling behaviour of steel plate elements supported by a plastic foam material

  • Mahendran, M.;Jeevaharan, M.
    • Structural Engineering and Mechanics
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    • v.7 no.5
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    • pp.433-445
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    • 1999
  • Sandwich panels comprising steel facings and a polystyrene foam core are increasingly used as roof and wall claddings in buildings in Australia. When they are subjected to loads causing bending and/or axial compression, the steel plate elements of their profiled facing are susceptible to local buckling. However, when compared to panels with no foam core, they demonstrate significantly improved local buckling behaviour because they are supported by foam. In order to quantify such improvements and to validate the use of available design buckling stress formulae, an investigation using finite element analyses and laboratory experiments was carried out on steel plates that are commonly used in Australia of varying yield stress and thickness supported by a polystyrene foam core. This paper presents the details of this investigation, the buckling results and their comparison with available design buckling formulae.

A new innovative 3-unknowns HSDT for buckling and free vibration of exponentially graded sandwich plates resting on elastic foundations under various boundary conditions

  • Rabhi, Mohamed;Benrahou, Kouider Halim;Kaci, Abdelhakim;Houari, Mohammed Sid Ahmed;Bourada, Fouad;Bousahla, Abdelmoumen Anis;Tounsi, Abdeldjebbar;Adda Bedia, E.A.;Mahmoud, S.R.;Tounsi, Abdelouahed
    • Geomechanics and Engineering
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    • v.22 no.2
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    • pp.119-132
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    • 2020
  • In this study a new innovative three unknowns trigonometric shear deformation theory is proposed for the buckling and vibration responses of exponentially graded sandwich plates resting on elastic mediums under various boundary conditions. The key feature of this theoretical formulation is that, in addition to considering shear deformation effect, it has only three unknowns in the displacement field as in the case of the classical plate theory (CPT), contrary to five as in the first shear deformation theory (FSDT) and higher-order shear deformation theory (HSDT). Material characteristics of the sandwich plate faces are considered to vary within the thickness direction via an exponential law distribution as a function of the volume fractions of the constituents. Equations of motion are obtained by employing Hamilton's principle. Numerical results for buckling and free vibration analysis of exponentially graded sandwich plates under various boundary conditions are obtained and discussed. Verification studies confirmed that the present three -unknown shear deformation theory is comparable with higher-order shear deformation theories which contain a greater number of unknowns.

A new higher-order shear and normal deformation theory for the buckling analysis of new type of FGM sandwich plates

  • Chikr, Sara Chelahi;Kaci, Abdelhakim;Yeghnem, Redha;Tounsi, Abdelouahed
    • Structural Engineering and Mechanics
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    • v.72 no.5
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    • pp.653-673
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    • 2019
  • This work investigates a novel quasi-3D hyperbolic shear deformation theory is presented to discuss the buckling of new type of sandwich plates. This theory accounts for both shear deformation and thickness stretching effects by a hyperbolic variation of all displacements through the thickness. The enhancement of this formulation is due to the use of only five unknowns by including undetermined integral terms, contrary to other theories where we find six or more unknowns. It does not require shear correction factors and transverse shear stresses vary parabolically across the thickness. A new type of FGM sandwich plates, namely, both FGM face sheets and FGM hard core are considered. The governing equations and boundary conditions are derived using the principle of virtual displacements. Analytical solutions are obtained for a simply supported plate. The accuracy of the present theory is verified by comparing the obtained results with quasi-3D solutions and those predicted by higher-order shear deformation theories. The comparison studies show that the obtained results are not only more accurate than those obtained by higher-order shear deformation theories, but also comparable with those predicted by quasi-3D theories with a greater number of unknowns.

Buckling analysis of nanocomposite plates coated by magnetostrictive layer

  • Tabbakh, Moein;Nasihatgozar, Mohsen
    • Smart Structures and Systems
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    • v.22 no.6
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    • pp.743-751
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    • 2018
  • In this project, buckling response of polymeric plates reinforced with carbon nanotubes (CNTs) and coated by magnetostrictive layer was studied. The equivalent nanocomposite properties are determined using Mori-Tanak model considering agglomeration effects. The structure is simulated with first order shear deformation theory (FSDT). Employing strains-displacements, stress-strain, the energy equations of the structure are obtained. Using Hamilton's principal, the governing equations are derived considering the coupling of mechanical displacements and magnetic field. Using Navier method, the buckling load of the sandwich structure is obtained. The influences of volume percent and agglomeration of CNTs, geometrical parameters and magnetic field on the buckling load are investigated. Results show that with increasing volume percent of CNTs, the buckling load increases. In addition, applying magnetic field, increases the frequency of the sandwich structure.

Fabrication of Metallic Sandwich Plates with Inner Dimpled Shell Structure and Static Bending Test (딤플형 내부구조 금속 샌드위치 판재의 제작 및 정적 굽힘 실험)

  • Seong Dae-Yong;Jung Chang-Gyun;Yoon Seok-Joon;Lee Sang-Hoon;Ahn Dong-Gyu;Yang Dong-Yol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.6 s.249
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    • pp.653-661
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    • 2006
  • Metallic sandwich plates with various inner cores have important new features with not only ultra-light material characteristics and load bearing function but also multifunctional characteristics. Because of production possibility on the large scale and a good geometric precision, sandwich plates with inner dimpled shell structure from a single material have advantages as compared with other solid sandwich plates. Inner dimpled shell structures can be fabricated with press or roll forming process, and then bonded with two face sheets by multi-point resistance welding or adhesive bonding. Elasto-plastic bending behavior of sandwich plates have been predicted analytically and measured. The measurements have shown that elastic perfectly plastic approximation can be conveniently employed with less than 10% error in elastic stiffness, collapse load, and energy absorption. The dominant collapse modes are face buckling and bonding failure after yielding. Sandwich plates with inner dimpled shell structure can absorb more energy than other types of sandwich plates during the bending behavior.