Showing papers on "Sandwich panel published in 2017"
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, a numerical model was developed to predict the damage behaviors of composite sandwich structures with a honeycomb core subjected to low-velocity perforation impact, addressing the intra-laminar damage, interlaminar and adhesive delamination and strain rate effect of the materials.
151 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 nonlinear eigen frequency response of the functionally graded single-walled carbon nanotube reinforced sandwich structure is investigated numerically considering the Green-Lagrange nonlinear strain under uniform thermal environment.
Abstract: The nonlinear eigen frequency response of the functionally graded single-walled carbon nanotube reinforced sandwich structure is investigated numerically considering the Green-Lagrange nonlinear strain under uniform thermal environment. The mathematical model of the sandwich plate has been derived using the simple higher-order shear deformable kinematics including the temperature dependent properties of each constituent. The sandwich panel constitutes of graded carbon nanotube face sheets and homogeneous core. The desired nonlinear finite element solutions are obtained via the direct iterative method. Based on the necessary validation and convergence new results are computed for different design related parameters and discussed subsequently.
77 citations
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.
66 citations
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.
65 citations
TL;DR: An ultra-lightweight sandwich panel with perforated honeycomb-corrugation hybrid (PHCH) core is innovated as a novel sound absorber, which demonstrates great sound absorption as well as excellent mechanical performance as discussed by the authors.
62 citations
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.
62 citations
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.
58 citations
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, 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: The results indicate that a sparse distribution of FBG sensors (uniaxial strain measurements) is sufficient for predicting accurate full-field membrane and bending responses (deformed shapes) of the panel, including a true zigzag representation of interfacial displacements.
Abstract: This paper investigated the effect of sensor density and alignment for three-dimensional shape sensing of an airplane-wing-shaped thick panel subjected to three different loading conditions, i.e., bending, torsion, and membrane loads. For shape sensing analysis of the panel, the Inverse Finite Element Method (iFEM) was used together with the Refined Zigzag Theory (RZT), in order to enable accurate predictions for transverse deflection and through-the-thickness variation of interfacial displacements. In this study, the iFEM-RZT algorithm is implemented by utilizing a novel three-node C°-continuous inverse-shell element, known as i3-RZT. The discrete strain data is generated numerically through performing a high-fidelity finite element analysis on the wing-shaped panel. This numerical strain data represents experimental strain readings obtained from surface patched strain gauges or embedded fiber Bragg grating (FBG) sensors. Three different sensor placement configurations with varying density and alignment of strain data were examined and their corresponding displacement contours were compared with those of reference solutions. The results indicate that a sparse distribution of FBG sensors (uniaxial strain measurements), aligned in only the longitudinal direction, is sufficient for predicting accurate full-field membrane and bending responses (deformed shapes) of the panel, including a true zigzag representation of interfacial displacements. On the other hand, a sparse deployment of strain rosettes (triaxial strain measurements) is essentially enough to produce torsion shapes that are as accurate as those of predicted by a dense sensor placement configuration. Hence, the potential applicability and practical aspects of i3-RZT/iFEM methodology is proven for three-dimensional shape-sensing of future aerospace structures.
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, the high-order buckling and free vibration behaviors of two types sandwich beams including AL or PVC-foam flexible core and CNTs reinforced nanocomposite face sheets using generalized differential quadrature method (GDQM) are investigated.
Abstract: In the present study, the high-order buckling and free vibration behaviors of two types sandwich beams including AL or PVC-foam flexible core and CNTs reinforced nanocomposite face sheets using generalized differential quadrature method (GDQM) are investigated. The high-order sandwich panel theory (HSAPT) for AL or PVC-foam flexible is employed and also the modified couple stress theory (MCST) for the face sheets is used. It is noted that the core of first sandwich beam is Aluminum alloy foam with variable mechanical properties and the other consists of PVC-foam core with temperature dependent mechanical properties. The governing partial differential equations of motion for two types sandwich beam are derived using Hamilton's principle and then discretized by using GDQM. These formulations yield nine partial differential equations which are coupled in axial and transverse deformations. A parametric study is carried out to investigate the effect of some important parameters such as slenderness ratio, face sheet thickness, temperature rise. Although increasing slenderness ratio, reduce the 1st natural frequency and also critical buckling load, but the treatment is different for AL-FCSB and PVC-FCSB. It is found that at high temperatures, the PVC-FCSB frequency decreases with increasing face sheet thickness whereas for AL-FCSB at high-temperatures although the frequency is less for low slenderness ratio and high face sheet thickness, but with increasing slenderness ratio frequency increases. This behavior is due to the large effect of face sheet and their temperature dependence in short sandwich beams compared with long ones.
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 article, an innovative concept for a multifunctional structural battery using lithium-ion battery materials as load bearing elements in a sandwich panel construction has been demonstrated, and the structural battery prototype has exhibited an initial capacity of 17.85 Ah, an energy density of 248 WhµL−1, a specific energy of 102µWh·1, and a capacity retention of 85.8% after 190 charge-discharge cycles at ~C/3 rate and eight mechanical loading cycles (upto 1060 N).
Abstract: An innovative concept for a multifunctional structural battery using lithium-ion battery materials as load bearing elements in a sandwich panel construction has been demonstrated. The structural battery prototype has exhibited an initial capacity of 17.85 Ah, an energy density of 248 Wh L−1, a specific energy of 102 Wh kg−1, and a capacity retention of 85.8% after 190 charge–discharge cycles at ~C/3 rate and eight mechanical loading cycles (upto 1060 N). The mechanical stiffness in three-point bend tests follows expectations based on sandwich beam theory, proving that the battery materials are sharing in the load-carrying function of the sandwich panel. While areas for improvement of the fabrication and performance of the prototype still exist, the results of the current investigation demonstrate the promising potential of the proposed structural battery concept for the efficient use of space and mass in an electric vehicle.
TL;DR: In this paper, the authors proposed a double-layer perforated absorber (DLPA) for low-frequency noise absorption with a honeycomb core and non-perforated back panel.
Abstract: A novel class of low-frequency sound absorbers based on a honeycomb sandwich panel is theoretically designed and numerically demonstrated. The absorber with a remarkably small thickness (e.g., 1/131 of wavelength) is comprised of a perforated facesheet, a perforated honeycomb core and a non-perforated back panel. Built upon the classical microperforated panel absorber (MPPA), the idea of introducing a perforated honeycomb core which creates a double-layer perforated absorber (DLPA) without adding to the total thickness greatly enhances the low-frequency absorption performance. Theoretical predictions of the sound absorption coefficient are obtained and compared with numerical simulations obtained using the finite element method (FEM). A good agreement is achieved. The proposed sound absorber is promising for low-frequency noise absorption especially when limited space and high mechanical stiffness/strength are simultaneously demanded.
TL;DR: In this paper, a numerical strategy for describing the textile/concrete bond behavior in textile-reinforced concrete (TRC) composites that separates the cohesive and coulomb friction contributions is presented.
TL;DR: This paper describes the extension of a wave and finite element (WFE) method to the prediction of noise transmission through, and radiation from, infinite panels, and various example applications are presented to illustrate the approach.
Abstract: This paper describes the extension of a wave and finite element (WFE) method to the prediction of noise transmission through, and radiation from, infinite panels. The WFE method starts with a conventional finite element model of a small segment of the panel. For a given frequency, the mass and stiffness matrices of the segment are used to form the structural dynamic stiffness matrix. The acoustic responses of the fluids surrounding the structure are modelled analytically. The dynamic stiffness matrix of the segment is post-processed using periodic structure theory, and coupled with those of the fluids. The total dynamic stiffness matrix is used to obtain the response of the medium to an incident acoustic pressure. Excitation of the structure by oblique plane waves and a diffuse sound field are considered. The response to structural excitation and the consequent radiation are determined. Since the size of the WFE model is small, computational times are small. Various example applications are presented to illustrate the approach, including a thin isotropic panel, an antisymmetric, cross-ply sandwich panel and a symmetric panel with an orthotropic core.
TL;DR: In this paper, a stepwise graded density foam core, with increasing density away from the blast, reduces the deflection of the panel and damage sustained, while the skin material affects the extent of panel deflection and damage, lower strain to failure of carbon-fibre reinforced polymer (CFRP) skins reduces deflection but increases skin debonding.
Abstract: The tailorable mechanical properties and high strength-to-weight ratios of composite sandwich panels make them of interest to the commercial marine and naval sector, however, further investigation into their blast resilience is required. The experiments performed in this study aimed to identify whether alterations to the composite skins or core of a sandwich panel can yield improved blast resilience both in air and underwater. Underwater blast loads using 1.28 kg TNT equivalent charge at a stand-off distance of 1 m were performed on four different composite sandwich panels. Results revealed that implementing a stepwise graded density foam core, with increasing density away from the blast, reduces the deflection of the panel and damage sustained. Furthermore, the skin material affects the extent of panel deflection and damage, the lower strain to failure of carbon-fibre reinforced polymer (CFRP) skins reduces deflection but increases skin debonding. A further two panels were subjected to a 100 kg TNT air blast loading at a 15 m stand-off to compare the effect of a graded density core and the results support the underwater blast results. Future modelling of these experiments will aid the design process and should aim to include material damage mechanisms to identify the most suitable skins.
TL;DR: In this paper, the authors used Taylor's FSI method to calculate the pressure amplitudes to initiate damage in a sandwich panel with E-glass/Vinyl Ester facesheets and PVC H250 foam core.
TL;DR: In this article, the stiffness parameters of a structural web-core sandwich panel are determined by unit cell analysis and an exact general solution to the governing equations of the beam is formulated, and the static shape functions are used to derive consistent linear geometric stiffness and mass matrices.
TL;DR: In this article, the perforation resistance of clamped square sandwich panels with layered gradient metallic foam cores subjected to the hemispherical-nosed projectile impact was investigated numerically.
TL;DR: In this paper, the effects of yawed flow angle on the flutter and buckling properties of sandwich panels with triangular lattice core in supersonic airflow were investigated, which can provide theoretical basis for the use of sandwich structures in the design of aircraft.
Abstract: Sandwich structures with lattice core are novel composite structures, but the aeroelastic behaviors of them have not been fully studied. This paper is devoted to investigate the flutter and buckling properties of sandwich panels with triangular lattice core in supersonic airflow, and the active flutter and buckling control are also carried out, which can provide theoretical basis for the use of sandwich structures in the design of aircrafts. The unsteady aerodynamic pressure is evaluated by the supersonic piston theory in which the yawed flow angle is taken into account. Hamilton's principle with the assumed mode method is applied to formulate the equation of motion of the structural system. The active controller is designed by the displacement feedback method. Aeroelastic characteristics of the sandwich panels are studied, and the influences of the aerodynamic pressure on the frequency and mode shape of the panel are analyzed. The effects of yawed flow angle on the flutter properties of the sandwich panel are also analyzed. When considering the external in-plane load, the buckling behaviors of the sandwich panel are investigated. Moreover, the flutter and buckling properties between the sandwich and equivalent isotropic panels are compared to show the superior aeroelastic properties of the sandwich panels. The effects of piezoelectric patch placements on the active flutter control are analyzed. The optimal locations of piezoelectric actuator and sensor pairs are obtained by the genetic algorithm. The present study verifies that the sandwich structures have different aeroelastic and flutter suppression properties, which is useful in the research of lightweight sandwich materials.