Showing papers on "Aluminium foam sandwich published in 2023"

Failure behavior of a sandwich beam with GLARE face-sheets and aluminum foam core under three-point bending

Abstract: In this paper, the failure behavior of sandwich beams with aluminum foam core and glass fiber-reinforced epoxy/aluminum laminates (GLARE) face-sheets under three-point bending is studied by experimental and numerical methods. Through the observation of the experiments, the initial failure modes of GLARE sandwich beams are observed, i.e., indentation and core shear. The deformation and failure process of GLARE sandwich beams are explored. Finite element simulations are performed by using ABAQUS software, and the numerical results agree well with experimental results for peak loads of GLARE sandwich beams. The effects of geometrical and material parameters on the peak loads of GLARE sandwich beams are discussed in details. It is shown that the peak loads and energy absorption of GLARE sandwich beams increase with the increase of face-sheet thickness and foam strength and the decrease of span length. The effects of elastic modulus of foam and fiber laying angle of face-sheet are very small.

Impact Resistance of a Fiber Metal Laminate Skin Bio-Inspired Composite Sandwich Panel with a Rubber and Foam Dual Core

Abstract: This paper reports the development of a novel bio-inspired composite sandwich panel (BCSP) with fiber metal laminate (FML) face sheets and a dual core to improve the low-velocity impact behavior based on the woodpecker’s head layout as a design template. The dynamic response of BCSP under impact load is simulated and analyzed by ABAQUS/Explicit software and compared with that of the composite sandwich panel (CSP) with a single foam core. The impact behavior of BCSP affected by these parameters, i.e., a different face sheet thickness, rubber core thickness and foam core height, was also reported. The results show that BCSP has superior impact resistance compared to CSP, with a lower damage area and smaller deformation, while carrying a higher impact load. Concurrently, BCSP is not highly restricted to any particular region when dealing with stress distributions. Compared to CSP, the bottom skin maximum stress value of BCSP is significantly reduced by 2.4–6.3 times at all considered impact energy levels. It is also found that the impact efficiency index of BCSP is 4.86 times higher than that of CSP under the same impact energy, indicating that the former can resist the impact load more effectively than the latter in terms of overall performance. Furthermore, the impact resistance of the BCSP improved with the increase in face sheet thickness and rubber core thickness. Additionally, the height of the foam core has a notable effect on the energy absorption, while it does not play a significant role in impact load. From an economic viewpoint, the height of the foam core retrofitted with 20 mm is reasonable. The results acquired from the current investigation can provide certain theoretical reference to the use of the bio-inspired composite sandwich panel in the engineering protection field.

High strain-rate deformation analysis of open-cell aluminium foam

Abstract: This study investigated the high-strain rate mechanical properties of open-cell aluminium foam M-pore®. While previous research has examined the response of this type of foam under quasi-static and transitional dynamic loading conditions, there is a lack of knowledge about its behaviour under higher strain rates (transitional and shock loading regimes). To address this gap in understanding, cylindrical open-cell foam specimens were tested using a modified Direct Impact Hopkinson Bar (DIHB) apparatus over a wide range of strain rates, up to 93 m/s. The results showed a strong dependency of the foam's behaviour on the loading rate, with increased plateau stress and changes in deformation front formation and propagation at higher strain rates. The internal structure of the specimens was examined using X-ray micro-computed tomography (mCT). The mCT images were used to build simplified 3D numerical models of analysed aluminium foam specimens that were used in computational simulations of their behaviour under all experimentally tested loading regimes using LS-DYNA software. The overall agreement between the experimental and computational results was good enough to validate the built numerical models capable of correctly simulating the mechanical response of analysed aluminium foam at different loading rates.

Performance of foam-filled kirigami corrugated sandwich panels as sacrificial cladding against blast loads

Abstract: In this study, the blast mitigation performance of kirigami corrugated (KC) panels filled with polyurethane foam as sacrificial cladding was investigated. Firstly, the effect of filling polyurethane (PU) foam on the energy absorption capacity and deformation mode of KC units was investigated by quasi-static compression. Numerical model was then built and validated. Following this, blast simulations were conducted to investigate the protective effectiveness of the aluminum foam panel, KC panel, and foam-filled KC panel as cladding for comparison. The blast loading effects on the structure without protection were also calculated and compared with different types of cladding. The key evaluating parameters, including peak transmitted load to the protected structure, energy absorption, and the crushed depth of the front plate, were used to evaluate the mitigation performance under various blast loads. The numerical results demonstrated the superior mitigating performance of foam-filled KC sandwich structures under various blast loading scenarios. The proposed foam-filled KC panel shows a higher energy absorption capacity than aluminum foam panels. The foam-filled KC panels with various densities of PU foam under different blast loads were also conducted to investigate its influence on blast mitigation performance. It was found that the second peak in the transmitted load can be reduced for KC panels with a higher density of the foam, as it leads to higher energy absorption capacity and later densification of the core against blast loads.

Experimental and numerical study on the dynamic response of aluminum alloy wood sandwich panels under high-velocity impact

Abstract: The purpose of this study was to investigate the high-velocity impact response and failure modes of three-layer sandwich panels consisting of aluminum alloy sheets and plywood. The energy absorption mechanism and interaction between the plywood core and aluminum alloy panels were investigated by a high-velocity impact test. Different types of bullets were used in the impact test, and impact velocity parameters were obtained using a high-velocity camera to assess damage patterns. A full-scale finite element model was established to simulate the response mode of plywood sandwich under high-velocity impact. After the finite element model was verified by the experimental results, the energy absorption of the sandwich structure was further discussed. The results showed that the sandwich structure provided better protection than the double-layer structure. The analysis and predictions were in good agreement with the experimental results and numerical calculations. The experimental and numerical studies proposed in this paper are expected to provide new references and ideas for the design of multilayer structures with better impact resistance and lightweight characteristics.

The Influence of Material Configuration of Fibre-Metal Laminates with Alumina Core on Flexural Strength

Abstract: Abstract Fibre metal laminates (FMLs) consisting of layers made of PA6 polyamide prepregs reinforced with glass and carbon fibres and an aluminium alloy core are the new variant of the other types used by aerospace FML materials such as GLARE or CARALL. By using a thermoplastic matrix, they can be shaped by stamping processes, which allows for a more efficient production process than classical laminating methods such as vacuum bagging. In addition to the improved impact energy absorption efficiency, the metallic core can be utilised to effectively bond the composite part to adjacent metallic structures. This article presents the influence of the material configuration of fibre-metal laminates consisting of continuous fibre-reinforced thermoplastic outer layers integrated with a layer of metallic aluminium alloy inserts—a number of layers, type and direction of reinforcing fibres—on the static and fatigue flexural properties. In this study, eight laminate configurations were prepared using a one-step variothermal consolidation process. The results showed that in the three-point flexural fatigue test, the samples exceeded 106 cycles at stresses <30% of the static bending strength. Laminates with predominantly longitudinally reinforced layers showed the highest fatigue strength among the FML samples analysed. The type of reinforcing fibres and the number of layers were less affected on the analysed mechanical properties.

Sandwich Structures With Bio-Inspired Viscoelastic Optimized Suture Face Sheets for Blast Mitigation

Abstract: In this paper, the performance of a novel bio-inspired face sheet in mitigating the effects of blast loading is investigated. The new design of the face sheet consists of an optimized bio-inspired suture structure sandwiched between two aluminium plates. The suture profile is obtained by performing structural optimization using Genetic Algorithm, wherein the dynamic responses obtained using a novel viscoelastic finite element formulation are used. The performance of this optimized suture-based face sheet is experimentally tested in a vertical shock tube which validates the results obtained using commercial finite element software Abaqus. The hybrid sandwich structure composed of an aluminium honeycomb core sandwiched between the developed face sheets is evaluated numerically for its blast resistance performance. The study shows that the proposed face sheet design, not only reduces the stresses in the face sheets significantly, but also reduces the core stresses compared to conventional aluminium face sheet–based sandwich structures. Several parametric studies are presented for axial and transverse shock loading on this hybrid sandwich structures that give more insight into their wave propagation characteristics.