Showing papers on "Sandwich-structured composite published in 2017"
TL;DR: In this paper, the authors combine 3D printing technique, numerical analysis, and experiments to design a new class of sandwich composites that exhibit various bending behaviors, including truss, conventional honeycomb, and re-entrant honeycomb topologies.
234 citations
TL;DR: In this paper, the authors examined the performance of a new protective system utilizing auxetic honeycomb-cored sandwich panels for mitigation of shock loads from close-in and contact detonations of high explosives.
229 citations
TL;DR: In this paper, the performance of composite panels with auxetic lattice cores confined between metallic facets for localised impact resistance applications is numerically studied, considering the rate-dependent effects.
Abstract: Sandwich panels with auxetic lattice cores confined between metallic facets are proposed for localised impact resistance applications. Their performance under localised impact is numerically studied, considering the rate-dependent effects. The behaviour of the composite structure material at high strain rates is modelled with the Johnson-Cook model. Parametric analyses are conducted to assess the performance of different designs of the hybrid composite structures. The results are compared with monolithic panels of equivalent areal mass and material in terms of deformations and plastic energy dissipation. Design parameters considered for the parametric analyses include the auxetic unit cell effective Poisson’s ratio, thickness of the facet, material properties and radius of the unit cell’s struts. Significant reduction in computational time is achieved by modelling a quarter of the panel, with shell elements for facets and beam elements for the auxetic core. With projectile impacts up to 200 m/s, the auxet...
191 citations
TL;DR: In this paper, the effects of several key structural parameters on crashworthiness characteristics and collapse mechanism of honeycomb sandwich panels were explored through the experiments through the authors divulged that crashworthiness and collapse mode of sandwich structures were greatly influenced by the structural parameters under the TPB test.
172 citations
TL;DR: In this paper, a novel lightweight bio-inspired double-sine corrugated (DSC) sandwich structure has been proposed to enhance the impact resistance, which significantly improves the structural crashworthiness as well as reducing the initial peak force greatly.
92 citations
TL;DR: In this paper, the authors investigated the impact response and energy absorption properties of honeycomb sandwich panels subjected to a drop-weight impact under a spherical impactor and concluded that more than 80% of the impact energy is absorbed mostly by top face-sheet and honeycomb core.
89 citations
TL;DR: In this paper, the structural response of composite panels with triple layered graded honeycomb cores under blast loading was analyzed by using finite element software LS-DYNA after validation against the experiments and the structural deformation modes were classified into three types and the core layer deformation was divided into three regions.
88 citations
TL;DR: In this article, an experimental investigation on impact response of sandwich composite panels with thermoplastic and thermoset face-sheet is presented. And the authors show that sandwich composites must have the harmony between core and the face sheet material.
Abstract: This paper presents an experimental investigation on impact response of sandwich composite panels with thermoplastic and thermoset face-sheet. E-glass reinforced epoxy (thermoset) and polypropylene (thermoplastic) have been used to produce polymer composite face-sheets. PVC foam was used as a core material. Several low velocity impact tests were performed under various impact energies. Besides to the individual impact behavior of the thermoset and thermoplastic sandwich composites, the impact response of sandwich composites having hybrid sequences was also investigated. Along with images of damaged samples, variations of the impact characteristics such as absorbed energy, maximum contact force and maximum deflection of the samples are provided. Most particularly this study showed that sandwich composites must have the harmony between core and the face sheet material. The deformation required for core densification must be able to compensate by the face sheet material.
76 citations
TL;DR: In this paper, a higher-order shear deformation beam theory was proposed for free vibration analysis of functionally graded carbon nanotube-reinforced composite sandwich beams in a thermal environment.
Abstract: This article proposes a higher-order shear deformation beam theory for free vibration analysis of functionally graded carbon nanotube-reinforced composite sandwich beams in a thermal environment. The temperature-dependent material properties of functionally graded carbon nanotube-reinforced composite beams are supposed to vary continuously in the thickness direction and are estimated through the rule of mixture. The governing equations and boundary conditions are derived by using Hamilton's principle, and the Navier solution procedure is used to achieve the natural frequencies of the sandwich beam in a thermal environment. A parametric study is led to carry out the effects of carbon nanotube volume fractions, slenderness ratio, and core-to-face sheet thickness ratio on free vibration behavior of sandwich beams with functionally graded carbon nanotube-reinforced composite face sheets. Numerical results are also presented in order to compare the behavior of sandwich beams including uniformly distrib...
72 citations
TL;DR: In this paper, a review of the recent innovations of steel-concrete-steel (SCS) sandwich structures subject to blast, impact, fatigue, and static loads is presented.
71 citations
TL;DR: Vitale et al. as mentioned in this paper presented a paper on the work of the Instituto de Investigaciones en Ciencia y Tecnologia de Materiales (IICM) at the University of Mar del Plata in Argentina.
Abstract: Fil: Vitale, Juan Pablo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnologia de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingenieria. Instituto de Investigaciones en Ciencia y Tecnologia de Materiales; Argentina
TL;DR: In this article, the impact response of newly designed sandwich panels with aluminum (AL) foam core and metal fibre laminate (FML) skins, which are comprised of aluminium sheets and plain woven E glass fibre composite plies are investigated.
TL;DR: In this article, a finite element formulation based on a higher-order layerwise theory is presented for the first time to investigate thermally induced vibrations of functionally graded material (FGM) sandwich plates and shell panels.
TL;DR: In this article, a hot-press molding method was developed to manufacture all-composite sandwich panel with tetrahedral truss cores, and the out-of-plane compressive and in-plane shear behaviors of this structure were investigated by experiments.
Abstract: A novel hot-press molding method was developed to manufacture all-composite sandwich panel with tetrahedral truss cores in this paper. The out-of-plane compressive and in-plane shear behaviors of this structure were investigated by experiments. The results have shown that the tetrahedral truss core sandwich panel had a high compressive specific strength compared to metallic truss core sandwich panels. The node failure was observed in the experimental process. Finite element analysis (FEA) with a progressive failure model was involved to simulate the damage evolution process and predict the mechanical properties. The analytical formulae were also presented to predict the stiffness and strength of sandwich panel. Good agreement was found between FEA calculated results and the experimental results. It is expected that this study can provide useful information for the fabrication and application of all-composite tetrahedral truss core sandwich panel.
TL;DR: In this article, an interlocking orthogrid sandwich composite panels reinforced by carbon fibers were designed, made and tested to construct weight efficient aerospace sandwich structures, and it was concluded that interlocking Orthogrid provides a simple but efficient way to construct lightweight sandwich composite.
TL;DR: In this article, the thermo-fluidic properties of an ultralightweight X-type lattice cored sandwich panel with simultaneous thermal and mechanical load bearing capabilities are studied both experimentally and numerically.
TL;DR: In this article, the performance of composite sandwich structures with glass fiber reinforced plastic sheets and bio-coconut core was analyzed and compared for three points bending tests to study mechanical bending properties.
Abstract: Composite materials has recently been widely used in the automotive, aerospace and other fields due to its light weight and good performance. At the same time, biological materials are also being paid more attentions in industrial application fields because of its economic, environmental, renewable and other advantages. Coconut mesocarp was chosen to be the core of composite sandwich structures with sheets of glass fiber reinforced plastics and carbon fiber reinforced composite were studied. Energy absorption behaviors were analyzed and compared. The thickness of all composite sheets is 1mm and the thickness of coconut mesocarp core is 20mm. Static compression tests were made by using universal testing machine. Results show that the composite sandwich structure with glass fiber reinforced plastic sheets and coconut mesocarp core has 1.0J/g of per weight energy absorption, which is higher than 0.91J/g of the composite sandwich structures with carbon fiber reinforced composite sheets and coconut mesocarp core. However, the peak crushing force of the former is less than the latter. Therefore, composite sandwich structures with glass fiber reinforced plastic sheets were selected for three points bending tests to study mechanical bending properties. By contrast with metal sheets sandwich structure and aluminum sheets sandwich structure, specific energy absorption of glass fiber reinforced plastic sheets sandwich structure is 2 times as much as metal sheets sandwich structure and 3–7 times as much as aluminum sheets sandwich structure, which shows an excellent crashworthiness performance of sandwich structures with composite sheets and bio coconut core.
TL;DR: In this paper, the authors investigate the crashworthiness of carbon fiber reinforced plastic (CFRP) sandwich panels filled with different reinforced materials under quasi-static compression and low velocity impact loading.
TL;DR: In this paper, the authors present the results of experimental and numerical analyses of the flexural vibration behavior of bio-based sandwich structures and their composite faces, and particularly their damping properties.
Abstract: This paper presents the results of experimental and numerical analyses of the flexural vibration behaviour of bio-based sandwich structures and their composite faces, and particularly their damping properties. The material studied is made up of two skins made of a thermoplastic matrix reinforced by flax fibres and a balsa wood core. The faces and the whole sandwich structures were produced by liquid resin infusion. First, experimental tests were performed on the skins. Free vibration tests were carried out on unidirectional and cross-ply laminates in a clamped free configuration to investigate the influence of the fibre orientation and stacking sequence on the dynamic stiffness and loss factors. Then, the damping behaviour of the balsa core was studied through several free vibration tests. In addition, the damping properties of sandwich beams with different thicknesses were measured and discussed. Finally, a finite elements model was used to calculate the resonance frequencies and modal loss factors of different sandwich beams. Close correlation between the numerical and experimental results was observed. Finally, a modal strain energy method was used to evaluate the contribution of the skins and of the core to the damping properties of the different sandwich beams.
TL;DR: In this article, the authors investigated the pseudo-ductile flexural behavior of innovative sandwich beams using wood as core material and glass fibre reinforced polymer (GFRP) as surface skins and inner lattice-webs.
Abstract: This paper investigates the pseudo-ductile flexural behavior of innovative sandwich beams using wood as core material and glass fibre reinforced polymer (GFRP) as surface skins and inner lattice-webs. The beams were prepared by a vacuum assisted resin infusion process. An experimental study was carried out to evaluate the stiffness and strength properties of the composite sandwich beams and reference wood beams under four-point bending. Ten sandwich beams were tested with different core configurations in comparison to two reference wood beams. The results showed that implementation of GFRP webs in the sandwich beams considerably improved their flexural performance, in association with a pseudo-ductile failure process and certain residual load-carrying capacity. Analytical formulas were developed to predict the bending stiffness and capacity of GFRP-wood sandwich beams. A comparison of the predicted and experimental results showed good agreement for mechanical characteristics of the GFRP-wood sandwich beams tested under four-point bending.
TL;DR: In this article, a 2D gradient auxetic core was used to optimize the vibrational properties of a hexagonal auxetic sandwich plate with a homogenized finite element model.
TL;DR: In this paper, an investigation into the effects of the matrix properties, bond length, bond thickness and bond width on the bond behavior between a composite sandwich panel and polymer matrix is discussed.
TL;DR: In this article, the authors evaluated the low frequency sound absorption coefficient (SAC) and sound transmission loss (STL) of corrugated sandwich panels with different perforation configurations.
TL;DR: In this paper, the impact response of a newly developed sandwich panel with aluminium foam core and fibre metal laminate (FML) skins, comprised of aluminium sheets and plain woven E glass fibres, is investigated.
TL;DR: In this article, the aerothermoelastic flutter and thermal buckling characteristics of sandwich panels with the pyramidal lattice core resting on elastic foundations in supersonic airflow are studied.
TL;DR: In this paper, a progressive failure model was used to predict the extent and type of damage during impact, which was then combined with the global finite element model to obtain residual strength predictions.
Abstract: Grid stiffened panels promise increased damage tolerance with reduced weight. Recent progress in automated manufacturing of composites has made it possible to produce such panels at low cost and thus has made them a competitive alternative to traditional skin-stiffened or sandwich panels. Fuselage skin panels typical of a 150 passenger aircraft were designed using an iterative process combining finite element models and local special purpose analysis methods. 40 cm by 30 cm panels, representing the final design, were fabricated using vacuum assisted resin transfer moulding. Pristine and impact damaged panels were tested in compression to failure. A progressive failure model was used to predict the extent and type of damage during impact. It was then combined with the global finite element model to obtain residual strength predictions. Analytical predictions were very close to test results. The fabrication method showed good quality and consistency and, when automated, can be used for production.
TL;DR: In this paper, a structural sandwich panel, consisting of a combination of concrete, insulation and connectors, was tested using a hot box apparatus to evaluate its thermal properties and energy efficiency.
TL;DR: In this paper, the impact of core geometry on sound transmission characteristics of sandwich panels has been explored and it is observed that, for a honeycomb core sandwich panel, one can select cell size as the parameter to reduce the weight with out affecting the sound transmission loss.
Abstract: Sandwich panel which has a design involving acoustic comfort is always denser and larger in size than the design involving mechanical strength. The respective short come can be solved by exploring the impact of core geometry on sound transmission characteristics of sandwich panels. In this aspect, the present work focuses on the study of influence of core geometry on sound transmission characteristics of sandwich panels which are commonly used as aircraft structures. Numerical investigation has been carried out based on a 2D model with equivalent elastic properties. The present study has found that, for a honeycomb core sandwich panel in due consideration to space constraint, better sound transmission characteristics can be achieved with lower core height. It is observed that, for a honeycomb core sandwich panel, one can select cell size as the parameter to reduce the weight with out affecting the sound transmission loss. Triangular core sandwich panel can be used for low frequency application due to its ...
TL;DR: In this article, the vibroacoustic problem of sound transmission across a rectangular double-wall sandwich panel clamp mounted on an infinite rigid baffle and lined with poroelastic materials is addressed analytically.
TL;DR: In this paper, the use of expanded cork (a 100% natural lightweight agglomerate material) as a core material in composite sandwich structures with carbon fiber face sheets was investigated.
Abstract: This study investigates the use of expanded cork (a 100% natural lightweight agglomerate material) as a core material in composite sandwich structures with carbon fiber face sheets. The characterization performed focused particularly on energy absorption capability. Rohacell® 110 IG, a synthetic foam commonly used as a core material in high performance aerospace applications, was also used and characterized to compare the energy absorbing characteristics of the sandwich composites. Bending tests were done to examine the stiffness of the sandwich beams. Wavenumber and damping tests were performed to characterize the acoustic and vibrational damping properties of the composites. Both full penetration and partial penetration low velocity impact tests were completed to determine the damage resistance of the composites. It was seen that when compared to the synthetic foam, expanded cork showed a decrease in bending stiffness, but a large improvement in acoustic, damping, and impact damage resistance characteristics. It seems that expanded cork could be an attractive lightweight sandwich core material that will allow for increased energy absorption and will also reduce the carbon footprint of the structures.