Papers by Keyword: Sandwich Beam

Abstract: The vibration response of laminated sandwich beams, with a core layer filled with various foam materials, referred to as Foam-based Sandwich Laminated Composite (FSLC) beams, has been studied. First, to precisely capture the varying material properties across the thickness of the sandwich beams, a modified layerwise displacement theory was employed. This approach addresses the inhomogeneity of the foam material in the core, yielding more accurate results than conventional classical laminated plate theories typically used for analyzing laminated composite structures. Secondly, to assess the impact of foam properties on dynamic behavior, FSLC beams incorporating three distinct types of foam have been analyzed. Thirdly, a proof-of-concept experimental test was conducted to demonstrate the functionality of the proposed model under dynamic loading conditions. The natural frequencies and damping coefficients of the FSLC beams have been determined using the modified layerwise theory. The dynamic response of the FSLC beams under impulse loading has also been analyzed. It was observed that the addition of foam in the core layer enhances the damping properties of the sandwich beam by approximately ten percent while reducing the natural frequencies by approximately five percent under all types of loading considered.

Abstract: Composite sandwich plates and beams are increasingly employed as an engineering material in structures such as airplanes, ships, bridges, and vehicles because of their superb strength to weight ratio. Understanding a sandwich structure’s failure mechanism is a prerequisite for a safety design. In this paper, we employ a new experimental technique called DVSP (Digital Volumetric Speckle Photography) to map the interior deformation of a short composite sandwich beam under three-point bending. 3D displacement fields and shear strain fields of 5 transverse and 4 longitudinal sections of the beam are mapped quantitatively in detail as a function of increasing load. The beam fails in delamination of the interface between the face sheet and core.

Abstract: In this paper, the mechanical behavior in three-point bending was investigated for four different sandwich beams composed of aluminum alloy 1050 H24 faces and Necuron rigid polyurethane foams. The tests were conducted according to the recommendations of ASTM C393-00. Three different failure modes were observed (yielding of faces, face and core indentation and shear of core), being in accordance with the modes deducted from the calculated values of bending and shear stresses.

Abstract: This paper presents the investigation on the flexural performance of steel concrete steel (SCS) sandwich beam comprising of fibre reinforced foamed concrete (FRFC) as a core concrete, sandwiched between the two steel plates. The steel plates were connected by a J-hook shear connector in order to develop a composite action between the plates and core concrete. The light weight foamed concrete having a density ranged from 1400 to 1450 kg/m³. The SCS sandwich beams were tested under a static gradual loading up to failure to examine its flexural behaviour. The test results revealed that the proposed SCS sandwich beam with FRFC increased the load carrying capacity and ductility performance. The finite element based modelling has also been conducted for the corroboration of test results. A reasonably close agreement has been obtained between the experimental results and predicted values.

Abstract: Bending properties and failure modes of sandwich structure with carbon fiber composite M-type folded cores were investigated and presented in this paper. Three point bending responses of both sandwich beams were measured. The finite element method was utilized to determine deformation mode of sandwich beam with M-type folded cores. Cores buckling and debonding have been studied under three point bending and the maximum displacement was also studied using FE-analytical and experimental methods.

Abstract: This study deals with the frequency analysis of Nano-sandwich-structure with nonlocal effect. The model takes into account the flexibility of the sandwich core while the faces are treat as beams. The different stiffness of core will impart different vibration characteristic of the structure. To examine free vibrations of Nano-sandwich-structure, nonlocal elasticity theory has been applied. In this paper an investigation is carried out to understand the small-scale effects in the free vibration. The boundary conditions of simply-supported conditions are described here. Further the effects of scale coefficient and stiffness parameter are studied in this manuscript.

Abstract: In this paper static analysis of a cantilever functionally graded sandwich beam under uniform distributed loads is carried out numerically. The beam is composed of two glass fiber reinforced plastic (GFRP) facesheets and a graded Corecell A-series foam core. The composite skins and foam core are stitched together using the same glass fiber. A finite element (FE) model is developed employing a FE commercial code to determine the stresses and deflections. To find the effect of quality of foam gradation through the thickness of the core on the deflections and stresses numerical experiments are performed. Results revealed that the quality of gradation of the foam core affected the displacements and stresses significantly so that an optimal gradation of foam can minimize the deflection, stresses and weight of the sandwich beam.

Abstract: A new sandwich beam theory is proposed by introducing independent variables of the displacements of face sheets, middle plane of soft core according to the incompression in transverse direction of traditional sandwich beam theory. Based on Hamilton principal, the governing equation of the system is established. Galerkin truncation method was used to solve the governing equation. It was found that (1) the first mode of the system displays that it is consistent with the traditional sandwich beam theory; (2) the second mode of the system shows that the soft core is in the state of tension or in compression; (3) the third mode of the system displays that the upper part and lower part of soft core are in different state (tension or compression); (4) The incompressible model of sandwich beam is the special form of soft sandwich beam we establish in this paper.

Abstract: The transverse vibration characteristic of the viscoelastic sandwich beam with axial speed is studied under the coupled temperature field and displacement field. Based on the theory of Euler - Bernouli beam and the constitutive relation of Kelvin viscoelastic material model, the transverse vibration equation of the axially moving beam is established ; considering the interaction of the material deformation and the heat conduction, the coupled governing equation of the beam is obtained. and the coupled thermoelastic dynamics system are obtained by Galerkin method. The related thermal parameters on the vibration frequency are analyzed by using numerical method.

Abstract: The nonlinear dynamic behaviour of sandwich beams with different cores under transverse cycling loads is investigated in this paper. Based on Euler-Bernoulli beam theory, the second-order nonlinear ordinary differential equation of the sandwich beams with different cores is established by applying Hamilton’s principle and Galerkin method. The effects of the cores of metal foam and lightweight wood and porous metal fiber as well as pyramid lattice structure on the dynamic behaviour are studied through numerical simulations. It is shown that the dynamic behaviour of sandwich beams is not solely determined by and