• Title/Summary/Keyword: Sandwich Beam

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Stochastic vibration response of a sandwich beam with nonlinear adjustable visco-elastomer core and supported mass

  • Ying, Z.G.;Ni, Y.Q.;Duan, Y.F.
    • Structural Engineering and Mechanics
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    • v.64 no.2
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    • pp.259-270
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    • 2017
  • The stochastic vibration response of the sandwich beam with the nonlinear adjustable visco-elastomer core and supported mass under stochastic support motion excitations is studied. The nonlinear dynamic properties of the visco-elastomer core are considered. The nonlinear partial differential equations for the horizontal and vertical coupling motions of the sandwich beam are derived. An analytical solution method for the stochastic vibration response of the nonlinear sandwich beam is developed. The nonlinear partial differential equations are converted into the nonlinear ordinary differential equations representing the nonlinear stochastic multi-degree-of-freedom system by using the Galerkin method. The nonlinear stochastic system is converted further into the equivalent quasi-linear system by using the statistic linearization method. The frequency-response function, response spectral density and mean square response expressions of the nonlinear sandwich beam are obtained. Numerical results are given to illustrate new stochastic vibration response characteristics and response reduction capability of the sandwich beam with the nonlinear visco-elastomer core and supported mass under stochastic support motion excitations. The influences of geometric and physical parameters on the stochastic response of the nonlinear sandwich beam are discussed, and the numerical results of the nonlinear sandwich beam are compared with those of the sandwich beam with linear visco-elastomer core.

Dynamic/static stability characteristics of sandwich FG porous beams

  • Weijia Yu;Linyun Zhou
    • Steel and Composite Structures
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    • v.46 no.2
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    • pp.203-210
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    • 2023
  • In the present research, dynamic deflections of a sandwich beam having functionally graded (FG) porous core have been investigated assuming that the sandwich beam is exposed to a pulse load of blast type. The two layers of sandwich beam have been made of a polymeric matrix reinforced by graphene oxide powder (GOP). The micromechanical formulation of the layers has been done via Halpin-Tsai model. The solution method is chosen to be Ritz method which is an efficient method to solve the system of equations of beams modeled based on a higher-order theory. To derive the time history of sandwich beam under pulse load, Laplace method has been used. The porosity content of the core, the GOP content of the layers, thickness of the layer and also duration of the applied load have great influences of the responses of sandwich beam.

Universal Theory for Planar Deformations of an Isotropic Sandwich Beam (등방성 샌드위치 빔의 평면 변형을 위한 통합 이론)

  • Lee, Chang-Yong
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.7
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    • pp.35-40
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    • 2020
  • This work is concerned with various planar deformations of an isotropic sandwich beam, which generally consists of three layers: two stiff skin layers and one soft core layer. When one layer of the sandwich beam is modeled as a beam, the variational-asymptotic method is rigorously used to construct a zeroth-order beam model, which is similar to a generalized Timoshenko beam model capable of capturing the transverse shear deformations but still carries out the zeroth-order approximation. To analyze the planar sandwich beam, the sum of the energies of the two skin layers and one core layer is then formulated with different material and geometric properties and represented by a universal beam model in terms of the core-layer kinematics through interface displacement and stress continuity conditions. As a preliminary validation, two extreme examples are presented to demonstrate the capability and accuracy of this present approach.

Assessment of nonlinear stability of geometrically imperfect nanoparticle-reinforced beam based on numerical method

  • Zheng, Yuxin;Jin, Hongwei;Jiang, Congying
    • Advances in nano research
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    • v.13 no.2
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    • pp.113-120
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    • 2022
  • In this paper, a finite element (FE) simulation has been developed in order to examine the nonlinear stability of reinforced sandwich beams with graphene oxide powders (GOPs). In this regard, the nonlinear stability curves have been obtained asuming that the beam is under compressive loads leading to its buckling. The beam is considered to be a three-layered sandwich beam with metal core and GOP reinforced face sheets and it is rested on elastic substrate. Moreover, a higher-order refined beam theory has been considered to formulate the sandwich beam by employing the geometrically perfect and imperfect beam configurations. In the solving procedure, the utalized finite element simulation contains a novel beam element in which shear deformation has been included. The calculated stability curves of GOP-reinforced sandwich beams are shown to be dependent on different parameters such as GOP amount, face sheet thickness, geometrical imperfection and also center deflection.

Forced vibration analysis of functionally graded sandwich deep beams

  • Akbas, Seref D.
    • Coupled systems mechanics
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    • v.8 no.3
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    • pp.259-271
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    • 2019
  • This paper presents forced vibration analysis of sandwich deep beams made of functionally graded material (FGM) in face layers and a porous material in core layer. The FGM sandwich deep beam is subjected to a harmonic dynamic load. The FGM in the face layer is graded though the layer thickness. In order to get more realistic result for the deep beam problem, the plane solid continua is used in the modeling of The FGM sandwich deep beam. The equations of the problem are derived based the Hamilton procedure and solved by using the finite element method. The novelty in this paper is to investigate the dynamic responses of sandwich deep beams made of FGM and porous material by using the plane solid continua. In the numerical results, the effects of different material distributions, porosity coefficient, geometric and dynamic parameters on the dynamic responses of the FGM sandwich deep beam are investigated and discussed.

Bending and buckling analysis of sandwich Reddy beam considering shape memory alloy wires and porosity resting on Vlasov's foundation

  • Bamdad, Mostafa;Mohammadimehr, Mehdi;Alambeigi, Kazem
    • Steel and Composite Structures
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    • v.36 no.6
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    • pp.671-687
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    • 2020
  • The aim of this research is to analyze buckling and bending behavior of a sandwich Reddy beam with porous core and composite face sheets reinforced by boron nitride nanotubes (BNNTs) and shape memory alloy (SMA) wires resting on Vlasov's foundation. To this end, first, displacement field's equations are written based on the higher-order shear deformation theory (HSDT). And also, to model the SMA wire properties, constitutive equation of Brinson is used. Then, by utilizing the principle of minimum potential energy, the governing equations are derived and also, Navier's analytical solution is applied to solve the governing equations of the sandwich beam. The effect of some important parameters such as SMA temperature, the volume fraction of SMA, the coefficient of porosity, different patterns of BNNTs and porous distributions on the behavior of buckling and bending of the sandwich beam are investigated. The obtained results show that when SMA wires are in martensite phase, the maximum deflection of the sandwich beam decreases and the critical buckling load increases significantly. Furthermore, the porosity coefficient plays an important role in the maximum deflection and the critical buckling load. It is concluded that increasing porosity coefficient, regardless of porous distribution, leads to an increase in the critical buckling load and a decrease in the maximum deflection of the sandwich beam.

Experimental Investigation of Shear Modulus of a Core in a Metallic Sandwich Plate with a Truss Core (트러스형 금속 샌드위치 판재에서 심재의 전단특성계수의 실험적 결정)

  • Jung, Chang-Gyun;Seong, Dae-Young;Yang, Dong-Yol;Moon, Kyung-Je;Ahn, Dong-Gyu
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.8 s.197
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    • pp.67-73
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    • 2007
  • A sandwich plate with a truss core is composed of two face sheets and a pyramidal truss core between face sheets. This paper shows how to estimate the shear modulus of a truss core, experimentally. To determine the shear modulus of truss cores, 3-point bending tests are performed. For tests, metallic sandwich beams with truss cores are fabricated. Two kinds of truss cores are tested to investigate the shear modulus. Each test is repeated under different widths in order to increase accuracy. As a result, the shear modulus of sandwich beam is properly calculated. The deflection of a sandwich beam with a truss core by shear deformation takes the major contribution of the total deflection and the shear modulus of sandwich beam should be considered whenever it is designed.

Finite element modeling and bending analysis of piezoelectric sandwich beam with debonded actuators

  • Rao, K. Venkata;Raja, S.;Munikenche, T.
    • Smart Structures and Systems
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    • v.13 no.1
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    • pp.55-80
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    • 2014
  • The present work pays emphasis on investigating the effect of different types of debonding on the bending behaviour of active sandwich beam, consisting of both extension and shear actuators. An active sandwich beam finite element is formulated by using Timoshenko's beam theory, characterized by first order shear deformation for the core and Euler-Bernoulli's beam theory for the top and bottom faces. The problem of debondings of extension actuator and face are dealt with by employing four-region model for inner debonding and three-region model for the edge debonding respectively. Displacement based continuity conditions are enforced at the interfaces of different regions using penalty method. Firstly, piezoelectric actuation of healthy sandwich beam is assessed through deflection analysis. Then the effect of actuators' debondings with different boundary conditions on bending behavior is computationally evaluated and experimentally clamped-free case is validated. The results generated will be useful to address the damage tolerant design procedures for smart sandwich beam structures with structural control and health monitoring applications.

An analytical method for free vibration analysis of functionally graded sandwich beams

  • Bouakkaz, K.;Hadji, L.;Zouatnia, N.;Adda Bedia, E.A.
    • Wind and Structures
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    • v.23 no.1
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    • pp.59-73
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    • 2016
  • In this paper, a hyperbolic shear deformation beam theory is developed for free vibration analysis of functionally graded (FG) sandwich 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 sandwich beam are assumed to vary according to power law distribution of the volume fraction of the constituents. The core layer is still homogeneous and made of an isotropic material. Based on the present refined beam theory, the equations of motion are derived from Hamilton's principle. Navier type solution method was used to obtain frequencies. Illustrative examples are given to show the effects of varying gradients and thickness to length ratios on free vibration of functionally graded sandwich beams.

Nonlinear stability analysis of porous sandwich beam with nanocomposite face sheet on nonlinear viscoelastic foundation by using Homotopy perturbation method

  • Rostamia, Rasoul;Mohammadimehr, Mehdi
    • Steel and Composite Structures
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    • v.41 no.6
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    • pp.821-829
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    • 2021
  • Nonlinear dynamic response of a sandwich beam considering porous core and nano-composite face sheet on nonlinear viscoelastic foundation with temperature-variable material properties is investigated in this research. The Hamilton's principle and beam theory are used to drive the equations of motion. The nonlinear differential equations of sandwich beam respect to time are obtained to solve nonlinear differential equations by Homotopy perturbation method (HPM). The effects of various parameters such as linear and nonlinear damping coefficient, linear and nonlinear spring constant, shear constant of Pasternak type for elastic foundation, temperature variation, volume fraction of carbon nanotube, porosity distribution and porosity coefficient on nonlinear dynamic response of sandwich beam are presented. The results of this paper could be used to analysis of dynamic modeling for a flexible structure in many industries such as automobiles, Shipbuilding, aircrafts and spacecraft with solar easured at current time step and the velocity and displacement were estimated through linear integration.