Aluminum Honeycomb Sandwich Panel Research Articles

An experimental study of multi-core composite aluminium honeycomb sandwich panels under low-velocity impacts

This paper aims to evaluate the impact response of the multi-core composite sandwich panels from low-velocity experiments. Geometrical parameters of sandwich panels like cell size, cell height, and facesheet thickness are varied and their effect on peak load, energy absorption, and efficiency is reported in this article. The effect of impact energy variation ongraded and non-graded types of sandwich panels is also studied. Based on these experiments suitable recommendations are given for impact energy absorber applications. From a crashworthiness point of view, graded multi-core composite sandwich panels are found to be more effective than non-graded ones.

Deformation behaviors of defective aluminum honeycomb sandwich panels subjected to in-panel compressive loading: An experimental study with mirror-assisted multi-view DIC

Honeycomb sandwich panels have been extensively utilized in the aerospace and automotive industries for their prominent advantages of energy absorption, high strength and tailorable anisotropic mechanical properties. Nevertheless, the common presence of local core-to-skin disbonding poses an urgent need to understand the mechanical behaviors of defective honeycomb sandwich panels. The present work investigates the deformation behaviors and evolutions of aluminum honeycomb sandwich panels with varying sizes of circular artificial core-to-skin disbonding defects using mirror-assisted multi-view digital image correlation (MV-DIC). Based on the 3D profiles and dual-surface deformation fields obtained with mirror-assisted MV-DIC, it is revealed that disbonding defects induced local surface undulations with severe local strain concentrations and determined the mode of gradual bending and buckling. Defects with a diameter below 20 mm induced minor local surface undulations and slight decreases in buckling load. When the diameters of defects reach 30 mm, extensive surface convex deformation occurs and the buckling load decreases by 23 %. The results validate mirror-assisted MV-DIC as a cost-effective and practical technique for characterizing dual-surface 3D deformation of sheet composite materials and structures.

Out-of-plane compressive response of aluminum honeycomb sandwich panels: Adhesive geometry and bonding effects

Lightweight aluminum honeycomb sandwich panels are widely used in industrial engineering, particularly in aircraft applications. Due to their thin-walled nature, the honeycomb cell walls are especially susceptible to buckling under out-of-plane compressive loading, while the adhesive fillet that secures the honeycomb to the face-sheet remains intact. This paper investigates the effect of the adhesive geometry and bonding constraints on the out-of-plane compressive response through experimental, Finite Element (FE), and mathematical methods. A hybrid method accounting for adhesive bonding between the face-sheet and the cell walls, and different adhesive fillet geometries was proposed to predict strain onset and stress-strain relationships during densification. The resulting stress-strain curves predicted the energy absorbed by the panels to within 3.5 % of the experimental results. The widely used material model for honeycomb core does not account for densification and underpredicted the absorbed energy by 15.6 %. These findings emphasize the need for detailed adhesive analysis in the design of lightweight, thin-walled sandwich structures.

Electromagnetic Force on an Aluminum Honeycomb Sandwich Panel Moving in a Magnetic Field.

This paper reports a method for calculating the electromagnetic force acting on an aluminum honeycomb sandwich panel moving in a magnetic field. This research is motivated by the non-contact electromagnetic detumbling technology for space non-cooperative targets. Past modeling of the electromagnetic forces and torques generally assumes that the target is homogeneous. However, aluminum honeycomb sandwich panels are extensively used in spacecraft structures to reduce weight without sacrificing structural strength and stiffness, which are so inhomogeneous and complicated that it is difficult to obtain the induced electromagnetic force even by numerical methods. An equivalent conductivity tensor of an aluminum honeycomb sandwich panel is proposed, which allows the aluminum honeycomb sandwich panel to be treated as a homogeneous structure when calculating the induced electromagnetic forces. The advantage of the equivalent conductivity tensor in the calculation of induced electromagnetic forces is verified by finite element simulations. The proposed method makes it possible to evaluate the electromagnetic force of a large aluminum honeycomb sandwich structure moving in a magnetic field.

Response of aluminium honeycomb sandwich panels under combined shock and impact loading: Experimental and numerical investigations

The performance of sandwich structures against individual shock loading and fragment impact loading has been extensively examined, but little is known about their performance in the presence of simultaneous shock and impact loading. Based on a recently developed composite projectile to simulate combined shock and single fragment impact loading, the performance of aluminum honeycomb core sandwich panels (HCSPs) against combined loading is methodically examined. The achieved results reveal that the combined loading exhibits a synergistic effect compared to the single loading, i.e., increased damage of the sandwich panel and enhanced perforation resistance of the sandwich panel. After that, a three-dimensional finite element simulation is performed to explore the underlying mechanism of the synergistic effect. Numerical analysis indicates that the increased damage is a result of perforation-induced reduction of load-carrying capacity of sandwich panel, while the enhanced perforation resistance is the result of deflecting-induced perforation time delay of the perforation process. Finally, the parametric investigation of sandwich geometries such as asymmetric face sheets, core density, and core height is comprehensively conducted. The gained results reveal that both performance and synergistic effect due to combined loading are sensitive to these parameters.

Determination of the effect of adhesive fillets and viscous damping on the dynamic response of aluminum honeycomb sandwich panels

The dynamic characteristics of an aluminum honeycomb sandwich panel are experimentally determined under free boundary conditions and the computational model is updated according to the experimental results. The study confirms that the adhesives used to bond the core and face sheets affect the dynamic response of the sandwich panel through the adhesive fillets formed between the face sheets and the core during the bonding process. The viscous damping of the structure is also determined by experimental modal analysis. It is observed that the results of the experimental and computational results agree well when the effects of adhesive fillets and viscous damping are considered. Furthermore, a dynamic response analysis under random vibration is conducted to reveal the differences between the results of the initial and the updated models.

Finite Element Simulation Analysis of Aluminum Honeycomb Sandwich Plate Penetration of Aircraft Under High-Speed Bird Impact

In the process of flight, the penetration caused by bird strikes will cause a significant decrease in the bearing capacity of the material, or even complete loss, which will lead to the accident of the aircraft. Therefore, it is of great significance to study the mechanical properties of aluminum honeycomb sandwich panels at different angles of high-speed bird impact. In this paper, finite element software is used to numerically analyze the penetration process. In this paper, the impact test of the aluminum honeycomb sandwich panel was carried out at 90°, 75°, 60° and 45° at the speed of 170m/s by using 1.8kg birdshot. Through finite element simulation analysis of the damage process, contact force and energy absorption rate of the aluminum honeycomb sandwich panel, it is found that when the bird projectile penetrates the aluminum honeycomb sandwich plate, the aluminum honeycomb sandwich in the impact center will be seriously deformed, torn and penetrated and failed. The angle of bird impact has a great influence on the peak contact force and the decay rate of contact force, the energy absorption effect increases exponentially with the decrease of the angle.

Evaluating UHMWPE-stuffed aluminium foam sandwich panels for protecting spacecraft against micrometeoroid and orbital debris impact

Robotic spacecraft shielding for protection against micrometeoroid impact is typically provided by existing structural panels, thermal insulation blankets, or reinforced component containers. Here the performance of an open cell aluminium foam core sandwich panel with intermediate ultra-high molecular weight polyethylene (UHMWPE) stuffing under hypervelocity impact of spherical aluminium projectiles was evaluated. Providing comparable structural and thermal performance as honeycomb sandwich panels, foam core sandwich panels have demonstrated improved impact shielding behaviour in existing studies. The inclusion of UHMWPE stuffing is found, through experimental testing and a comprehensive numerical study, to increase the shielding capability of foam core sandwich panels (40–80% increase in critical projectile diameter) for a modest weight penalty (25%). Compared to conventional aluminium honeycomb sandwich panels with equivalent weight, the improvement in shielding performance is >100%.

Multi-objective optimization of multi-core composite aluminum honeycomb sandwich panels for improved crashworthiness

This article presents the low-velocity impact response of the multi-core aluminum honeycomb sandwich panel with composite face sheets using LS-DYNA-based finite element simulation. The effect of geometric parameters like cell size, cell height, cell thickness, and facesheet thickness, on structural response, is explored. The interaction effect of these geometric parameters, effect of number of layers/cores and characteristic force-time and energy-time curves for multilayer composite sandwich panels are also studied. Finally, these geometric parameters are optimized for better crashworthiness designs, followed by crashworthiness design recommendations.

In-plane compressive response of composite sandwich panels with local-tight honeycomb cores

In the present study, honeycomb cores with periodic tight zones were proposed for carbon-fiber and aluminum-honeycomb sandwich panels by flattening hexagon-shaped cells of honeycomb walls. In-plane compression tests were performed for sandwich panels with three types of local-tight honeycomb cores to evaluate the effects of the local-tight configurations on mechanical properties and failure modes. Experimental results indicated that the mechanical properties of sandwich specimens were effectively increased by using the proposed local-tight honeycomb cores. In particular, the specific energy absorption of sandwich specimens with a local-orthogonal-tight core was increased by 400.46%. In addition, Digital Image Correlation (DIC) technique was employed to further investigate the compressive behaviors of the sandwich specimens with and without local-orthogonal-tight honeycomb cores. The experimental measurements and detailed DIC observations indicated that the local-orthogonal-tight honeycomb core sandwich structures, which provided improved load transferring paths and reduced mismatch between the high-stiffness face sheets and low-stiffness core, exhibited progressive crushing failure modes.

Risk-Based Hybrid Light-Weight Ship Structural Design Accounting for Carbon Footprint

The study aims to develop an integrating risk-based formulation and cost-benefit analysis for identifying an optimal ship hull structural design solution where the steel cargo holds aluminium honeycomb sandwich panels to replace inner side shells. The risk of progressive structural failure includes hazards related to environmental pollution due to accidental fuel and oil spills, possible loss of cargo, crew members and ship during operations, and air pollution during shipyard construction and ship voyages. The structural failure incorporates progressive time-dependent structural degradation coupled with ship hull load-carrying capacity in predicting structural integrity during the service life. The ship hull structural failure and associated risk are estimated over the ship’s service life as a function of the design solution. The carbon footprint and cost to mitigate the impact for the entire steel and hybrid ship hull structural solution implemented as a sustainable life cycle solution are analysed where the steel ship hull structure is built through primary construction. The cost of structural measures accounts for redesigning the ship structure and implementing aluminium honeycomb composite panels instead of steel plates, reducing steel weight, environmental pollution and cost and increasing the transported cargo and corrosion degradation resistance. It has been found that design solutions AHS1 and AHS2, in which aluminium honeycomb panels replace the inner steel shell plates, enhance the corrosion degradation resistance, and reduce the ship hull’s lightweight, reflecting a better beta-reliability index at the time of the first repair with a lower repair cost and more transported cargo. The cost of the ship associated with the design solutions AHS1 and AHS2 is about 11% lower than the steel solutions.

Shape sensing for CFRP and aluminum honeycomb sandwich panel using inverse finite element method with distributed fiber-optic sensors

Shape sensing for CFRP and aluminum honeycomb sandwich panel using inverse finite element method with distributed fiber-optic sensors

Comparative analysis of aluminium core honeycomb with 3D woven Kevlar honeycomb composite

Sandwich structures have a high capacity for stiffness, strength, and energy absorption, and are frequently used as lightweight composite components in shipbuilding and aeronautical engineering. In this work, mechanical characterisation of aluminium honeycomb and 3D-woven Kevlar honeycomb composite sandwich panels with respect to their flatwise, edgewise compression, and three-point bending tests was carried out. The experimental results show that the 3D-woven Kevlar honeycomb is better than the aluminium honeycomb for flatwise and three-point bending behaviour. In the case of edgewise compression, aluminium honeycomb shows significant results. Aluminium honeycomb cores show the plastic collapse mechanism, while Kevlar honeycomb indicates the occurrence of buckling before failure.

Numerical simulation of continuous laser microdrilling of ultrathick aluminum honeycomb sandwich panels

Numerical simulation of continuous laser microdrilling of ultrathick aluminum honeycomb sandwich panels

Cork/aluminium double-layer sandwich panels under impact loading for lightweight ship structures

To meet the reduction targets of greenhouse gas emissions by highly polluting vessels such as cruise ships, several strategies are possible: the introduction of new fuels (i.e. LNG, hydrogen and biofuel), the installation of more efficient engines, the electrification of the propulsion systems, the lightening of the structures, the energy efficiency improvement of the auxiliary services (i.e. air conditioning). In particular, vessels weight reduction can be achieved by introducing new materials. The aim of this work was to manufacture an innovative laminate, which comes from the combination of a cork layer and an aluminium honeycomb sandwich, intended to provide an eco-friendly and lightweight solution for structures potentially destined to marine applications, such as ship decks, hulls or cabins’ construction. The suggested solution is expected to combine several functions and properties, such as low density and thermal and acoustic insulation - which potentially influence propulsion and auxiliaries fuel consumption—as well as good mechanical performances. The investigation was particularly focused on the potentialities offered by the cork layer, traditionally addressed at insulation purposes, in supporting and enhancing the impact-absorption capabilities of the aluminium honeycomb structure, especially in view of the potential marine applications which often suffer from low-velocity impact events. Having a dual function: (i) to lighten the superstructures and (ii) to promote the thermal and acoustic insulation, by thus influencing, respectively, propulsion and auxiliaries fuel consumption. For instance, the suggested solution could be used for cabins’ construction. In the present work, the energy absorption capabilities of the new lightweight structure were evaluated by means of low-velocity impact tests. An excellent response, comparable to that of double-layer aluminium honeycomb sandwich panels, was observed, suggesting that the new structure is a promising and sustainable alternative for marine constructions.

Theoretical analysis of aluminum honeycomb sandwich panel supported by reinforced concrete wall under low-speed impact load

Abstract Honeycomb materials are widely used across engineering fields. The use of honeycomb sandwich structures as energy dissipation and impact protection materials for reinforced concrete components in the field of civil engineering is a novel concept. Therefore, it is of great significance to study the energy absorption characteristics, dynamic response theoretical model, and collapse energy dissipation theory for the use of honeycomb sandwich structures as protective materials. Based on the large-scale low-speed pendulum impact test and the corresponding finite element model, this study establishes an ideal model for the honeycomb sandwich panel under the impact of a square flat head and gives the corresponding theoretical derivation. At the same time, it puts forward a method to estimate the energy consumption and dynamic crushing distance based on the energy consumption theory angle of the covering layer.

Cost, Energy Efficiency and Carbon Footprint Analysis of Hybrid Light-Weight Bulk Carrier

Integrating innovative solutions for ship design has always been a great challenge for the maritime sector due to complex design and construction processes. With this scenario in mind, the objective of this study was to develop a procedure to evaluate the potential benefits arising from the integration of innovative light-weight structures in ship hull structural design. To achieve such an objective, a hybrid light-weight ship hull structural design solution, in which aluminium honeycomb sandwich panels were used to build the conventional steel inner side shell of the cargo holds, was adopted for a bulk carrier. The authors of this study used a multiple criteria decision-making approach. An optimal ship hull structural design solution was identified based on capital cost, voyage cost, annual cost, energy efficiency design index, dismantling–reselling cost, cargo transportation, energy consumption and carbon footprint. The optimal solution, identified with the multiple criteria decision-making approach, improved the ship’s efficiency and costs by combining the hybrid structural design with efficient cargo transportation. In addition, using recycled aluminium was found to be a promising strategy to reduce the energy consumption and carbon footprint related to the shipbuilding process.

Improvement of the structural, thermal, and mechanical properties of polyurethane adhesives with nanoparticles and their application to Al/Al honeycomb sandwich panels

Abstract Understanding the relationship between core/face adhesive interface and performance of MWCNT added nanoadhesives are essential for better designing and fabrication of aluminum honeycomb sandwich panels. In this study, we used multi-walled carbon nanotubes (MWCNTs) to prepare enhanced interfacial adhesion between honeycomb core and aluminum facesheet. MWCNTs are first introduced to isocyanate, and then MWCNTs/isocyanate blend poured into polyol to produce MWCNTs reinforced polyurethane (PU) nanoadhesives. The relationship between core/face adhesive interface and performance of MWCNT added nanoadhesives are investigated in detail in terms of thermogravimetric analyses (TGA), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, edge-wise compression tests, flat-wise tensile tests and three-point bending tests The experimental results showed that the MWCNT addition to PU adhesive led to enhanced thermal stability, flat-wise tensile strength and edge-wise compression strength for sandwich structures. This study gives a significant reference indicator on the fabrication of an improved core/face interface for obtaining sandwich panels with desired mechanical properties.

Dynamic responses and energy absorption of sandwich panel with aluminium honeycomb core under ice wedge impact

In this paper, the dynamic responses and energy absorption characteristics of aluminium honeycomb sandwich panels (AHSPs) under ice wedge impact are numerically and experimentally investigated. A three-dimensional nonlinear finite element model of AHSP under ice impact is established based on a concrete constitutive ice model in the commercial package ANSYS/LS-DYNA. The impact force-displacement curves and energy absorption properties as well as the crushing process of ice wedge are numerically achieved. In addition, the ice wedge impact tests of AHSPs were conducted by using a horizontal impact experimental apparatus. Furthermore, the effects of impact parameters and structural parameters on the dynamic responses and energy absorption are performed. Results show that the numerical results of ice wedge-AHSP impact dynamic responses are consistent well with the experimental results. The permanent deformation profiles of face sheets are approximately axisymmetric about the vertical and horizontal centerline. The ice impact energy is mainly converted into the plastic deformation energy of AHSP and rebound kinetic energy of ice wedge as well as the fracture energy of ice wedge. With the increase of the impact energy and thickness of face sheets, the energy dissipation ratio of ice broken increases dramatically and the energy dissipation by ice wedge makes an increasingly contribution to the impact energy absorption.

Fabrication of aluminum honeycomb cored carbon fabric/epoxy composite sandwich structures via vacuum assisted resin infusion technique

AbstractA detailed step‐by‐step fabrication procedural document of thin‐walled aluminum honeycomb sandwich composite structures, panels, and specimens using vacuum assisted resin infusion process was delivered in this paper. By and large, honeycomb sandwich structures are made by keeping the honeycomb core in between two face sheets, which are glued with the help of adhesives. In the present fabrication process, aluminum honeycomb core was glued in between the carbon fabric reinforced epoxy composite face sheets through vacuum assisted resin infusion technique. The present paper is aimed at fabricating two configurations of honeycomb sandwich composite panels namely, without considering any filler material inside the honeycomb cell, with considering the filler material inside the honeycomb cell. Plastic pellets made up of poly carbonate were considered as filler material for stiffening the aluminum honeycomb sandwich composite panels.