Artículos de revistas: "Tests sandwich"

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Prabhakaran, S., V. Krishnaraj, Hemashree Golla y M. Senthilkumar. "Biodegradation behaviour of green composite sandwich made of flax and agglomerated cork". Polymers and Polymer Composites 30 (enero de 2022): 096739112211036. http://dx.doi.org/10.1177/09673911221103602.

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Material experts are striving to use natural resources as skin and core in composite sandwiches to achieve light weight, biodegradability, and cost benefits. This paper reports one such newly developed green composite sandwich and its biodegradable behavior. The skin and core of newly developed sandwich are flax fiber and agglomerated cork respectively. This composite sandwich is manufactured by vacuum bagging technique in order to get higher volume fraction of fiber. The biodegradability testing of the composite sandwich has been executed by soil burial test. The verification of the same has been done using Scanning Electron Microscope (SEM) images, Fourier Transform Infrared Spectroscopy (FTIR) analysis and Thermoanalytical test. The test results portray the percentage of weight loss in the specimens and that, it increases with burial time. It also depicts that the newly developed Green Composite Sandwich (GCS) has 82% higher degradation than the Synthetic Composite Sandwich (SCS) taken for the comparison. SEM images show that the green composite sandwiches have lost their fibrous structure and cell wall surface due to the degradation. FTIR and Thermoanalytical tests also confirm the biodegradability of the developed green composite sandwich.

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Lin, Zhengjie, Hengliang Liang y Hongfei Zhou. "Forming pressure of PMI foam sandwich structure". Journal of Physics: Conference Series 2566, n.º 1 (1 de agosto de 2023): 012040. http://dx.doi.org/10.1088/1742-6596/2566/1/012040.

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Abstract In this study, the performance of A-reinforced sandwich structures made with polymethacrylimide (PMI) foam material is explored. The research focuses on comparing two forming methods, bonding and co-curing. It also tests the static properties of sandwich test pieces under different forming pressures. It reveals that the foam sandwich structure formed under the 0.15 MPa bonding process outperforms the rest regarding static properties. These findings provide valuable insights into the optimal structure-forming process for PMI foam sandwiches, paving the way for future advancements in this field.

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3

Li, Zhao, Hao Zhang, Qingyong Niu, Peng Wang y Xiaoming Cao. "Design of double-layered framed plate with equivalent impedance". MATEC Web of Conferences 380 (2023): 01018. http://dx.doi.org/10.1051/matecconf/202338001018.

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To get clear the vibration mechanism of sandwith shell using the experiment method, a double-layered plate is designed for the sandwich shell by matching the equivalent impedance. Numerical analysis is conducted, and In 10Hz-4000Hz, the differenceof impedance from double-layered plate and sandwich shell should be less than 10%. A new design is given for the double-layered plate, and which is quite simple for construction. Then, the double-layered plate could be applied to conduct series vibration tests to get clear the influence of sandwich core material on structural vibration, while it could also reduce the costs of money and construction time.

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4

Zhang, Zhen, Jian Guang Zhang, Xiu Zhi Liu, Yong Hai Wen y Shao Bo Gong. "Numerical and Experimental Studies of Composites Sandwich Structure with a Rectangular Cut-Out". Applied Mechanics and Materials 395-396 (septiembre de 2013): 891–96. http://dx.doi.org/10.4028/www.scientific.net/amm.395-396.891.

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Numerical and experimental study on honeycomb sandwich structure with a rectangular cut-out were carried out in this paper. Two designs were presented, with using a U-shaped sandwich structure or a combination of two separate sandwiches. Finite element models were developed and calculated using MSC.NASTRAN code by means of linear analysis and non-linear incremental deformation analysis. Compared with linear analysis, non-linear analysis was more suitable to evaluate the ability of sandwich structure with cut-out to resist compressive load. The results obtained from non-linear solution were verified by the supporting mechanical tests.

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5

Saifullah, Abu, Pappu Radhakrishnan, Lei Wang, Burhan Saeed, Forkan Sarker y Hom N. Dhakal. "Reprocessed Materials Used in Rotationally Moulded Sandwich Structures for Enhancing Environmental Sustainability: Low-Velocity Impact and Flexure-after-Impact Responses". Materials 15, n.º 18 (19 de septiembre de 2022): 6491. http://dx.doi.org/10.3390/ma15186491.

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In the rotational moulding industry, non-used, scrap, and waste purge materials have tremendous potential to be reprocessed and applied in skin-foam-skin sandwich structures to replace and reduce the use of virgin polymers. This approach not only encourages the re-use of these waste materials but also significantly contributes to reduce environmental impacts associated with the use of virgin polymers in this sector. The demand of rotationally moulded sandwich structures is rapidly increasing in automotive, marine, and storage tanks, where investigating their impact and after-impact responses are crucial. Hence, this study investigated the low-velocity impact (LVI) and flexure-after-impact (FAI) responses of rotationally moulded sandwich structures manufactured using reprocessed materials. Results obtained from LVI induced damage at two different incident energy levels (15 J, 30 J), and the residual flexural strength of impacted structures evaluated by three-points bending tests were compared with non-reprocessed sandwich structures (virgin materials). The impact damage progression mechanism was characterized using the X-ray micro-computer-tomography technique. Reprocessed sandwiches demonstrated 91% and 66% post-impact residual strength at 15 J and 30 J respectively, while for non-reprocessed sandwiches, these values were calculated as 93% and 88%. Although reprocessed sandwich structures showed a lower performance over non-reprocessed sandwiches, they have a strong potential to be used in sandwich structures for various applications.

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6

Kozak, Janusz. "Joints Of Steel Sandwich Structures". Polish Maritime Research 28, n.º 2 (1 de junio de 2021): 128–35. http://dx.doi.org/10.2478/pomr-2021-0029.

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Abstract Steel sandwich structures are perceived as alternatives to single-skin welded structures in the shipbuilding industry due its advantages like significant reduction of mass in relation to typical single skin structure. However, beside problems with their strength properties itself, applications in real structures requires of solving the problem of joining, both for connection sandwich to sandwich as well as sandwiches to single-shell structures. Proper design of joints is connected with some factors like lack of attempt to interior of panel, introduction of additional parts and welds with completely different stiffness. In the paper the results of laboratory fatigue tests of selected joints as well as numerical calculation of stressed for different kind of joints of sandwich structures are presented. As result of calculations optimisation of geometry for selected joints is performed.

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7

Hosseini, SM, A. Habibolahzadeh y J. Němeček. "Static and dynamic responses of a novel Al nanocomposite foam/sandwich structure under bending, impact and quasi-static compression tests". Journal of Sandwich Structures & Materials 21, n.º 4 (3 de julio de 2017): 1406–27. http://dx.doi.org/10.1177/1099636217717579.

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The aim of this study is to analyze mechanical properties of a new Al sandwich structure with a foam core reinforced by 0.75 wt% silicon carbide nanoparticles. The reinforced core as the main component of the sandwich structure is examined by nanoindentation, quasi-static compression, impact and three-point bending tests. The behavior of the nanocomposite foam core sandwiched with AA3103 facing sheets is also analyzed under three-point bending test. The results showed that the silicon carbide nanoparticles play an important role in enhancing the Young’s modulus and hardness of the metallic matrix, static compressive strength, energy absorption of the foam core as well as load carrying capacity and maximum deflection of the sandwich structure. However, they have no significant influence on the morphological features, impact and bending properties of the foam core. The effectiveness of the silicon carbide nanoparticles was dependent on the dominant deformation mode and failure mechanism of specimens under the applied loadings.

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8

Emi Nor Ain Mohammad, Nurul, Aidah Jumahat y Mohamad Fashan Ghazali. "Impact Properties of Aluminum Foam – Nanosilica Filled Basalt Fiber Reinforced Polymer Sandwich Composites". International Journal of Engineering & Technology 7, n.º 3.11 (21 de julio de 2018): 77. http://dx.doi.org/10.14419/ijet.v7i3.11.15934.

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This paper investigates the effect of nanosilica on impact and energy absorption properties of sandwich foam-fibre composites. The materials used in this study are closed-cell aluminum (Al) foam (as the core material) that is sandwiched in between nanomodified basalt fiber reinforced polymer (as the face-sheets). The face sheets were made of Basalt Fibre, nanosilica and epoxy polymer matrix. The sandwich composite structures are known to have the capability of resisting impact loads and good in absorbing energy. The objective of this paper is to determine the influence of closed-cell aluminum foam core and nanosilica filler on impact properties and fracture behavior of basalt fibre reinforced polymer (BFRP) sandwich composites when compared to the conventional glass fibre reinforced polymer (GFRP) sandwich composites. The drop impact tests were carried out to determine the energy absorbed, peak load and the force-deflection behaviour of the sandwich composite structure material. The results showed that the nanomodified BFRP-Al foam core sandwich panel exhibited promising energy absorption properties, corresponding to the highest specific energy absorption value observed. Also, the result indicates that the Aluminium Foam BFRP sandwich composite exhibited higher energy absorption when compared to the Aluminium foam GFRP sandwich composite.

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9

Elettore, Elena, Massimo Latour, Mario D’Aniello, Raffaele Landolfo y Gianvittorio Rizzano. "Prototype Tests on Screwed Steel–Aluminium Foam–Steel Sandwich Panels". Buildings 13, n.º 11 (13 de noviembre de 2023): 2836. http://dx.doi.org/10.3390/buildings13112836.

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Metal foams are newly developed engineered materials with attractive mechanical properties such as lightness, high resistance-to-weight ratio, and insulation capabilities. Lately, applications of these technologies have demonstrated the possibility of obtaining high-performance sandwich panels with steel skins and metal foam core, with potential applications across various fields. Within this framework, this work aims to assess the response of sandwich panels made of steel and aluminium foam to develop a new system of dry-assembled composite floors. The present study investigates a novel screwed steel–aluminium foam–steel (SSAFS) sandwich panel. This paper mainly describes and discusses the results of experimental tests devoted to evaluating the structural performance, mechanical properties, and suitability for practical applications of SSAFS. The fabrication process and the detailing of the steel skins and aluminium foam core assembly are also described. The results from the experimental tests revealed the potentialities of using SSAFS sandwich panels in terms of strength and stiffness, thus making them suitable for lightweight structural systems.

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10

Chróścielewski, Jacek, Marian Klasztorny, Mikołaj Miśkiewicz, Łukasz Pyrzowski, Magdalena Rucka y Krzysztof Wilde. "GFRP sandwich composite with PET core in shell structure of footbridge". Budownictwo i Architektura 13, n.º 2 (11 de junio de 2014): 183–90. http://dx.doi.org/10.35784/bud-arch.1894.

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The paper presents experimental study of sandwich composite used for an innovative foot-and-cycle bridge. The footbridge has a U-shaped shell structure made of sandwich consisting GFRP laminate covers and foam PET core. The bridge is manufactured using the infusion technology. Results of one and two directional tension tests of the laminates, compression tests of PET foam samples and 3-point as well as 4-point bending tests of sandwich beams are presented.

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11

Amde, Amde M., Amir Mirmiran y David Nelsen. "Stability Tests of Sandwich Composite Elastica Arches". Journal of Structural Engineering 128, n.º 5 (mayo de 2002): 683–86. http://dx.doi.org/10.1061/(asce)0733-9445(2002)128:5(683).

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12

Kajon, G., L. Monteleone y R. Steindler. "MONITORED BALLISTIC TESTS ON SHOCKPROOF SANDWICH GLASSES". Experimental Techniques 25, n.º 5 (septiembre de 2001): 27–31. http://dx.doi.org/10.1111/j.1747-1567.2001.tb00038.x.

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13

Altenbach, H. y E. Nast. "Multi-dimensional deformation tests of sandwich plates". Mechanics of Composite Materials 33, n.º 5 (septiembre de 1997): 430–40. http://dx.doi.org/10.1007/bf02256897.

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14

Mostafa, A. y K. Shankar. "Finite Element Study on the Influence of Shear Key Diameter on the Shear Performance of Composite Sandwich Panel with PU Foam Core". Applied Mechanics and Materials 376 (agosto de 2013): 103–7. http://dx.doi.org/10.4028/www.scientific.net/amm.376.103.

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The present study deals with the shear behavior of the composite sandwich panels comprised of Polyvinylchloride (PVC) and Polyurethane (PU) foam core sandwiched between Glass Fiber Reinforced Polymer (GFRP) skins using epoxy resin. Experiments have been carried out to characterize the mechanical response of the constituent materials under tension, compression and shear loading. In-plane shear tests for the sandwich panel reveal that the main failure mode is the delamination between the skin and the core rather than shearing the core itself since the skin-core interaction is the weakest link in such structure. The Finite Element Analysis (FEA) of the sandwich structure, based on the non-linear behavior of the foam core and skin-core cohesive interaction, shows that shear response and failure mode can be predicted with high accuracy.

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15

Mostafa, A. y K. Shankar. "In-Plane Shear Damage Prediction of Composite Sandwich Panel with Foam Core". Applied Mechanics and Materials 376 (agosto de 2013): 69–73. http://dx.doi.org/10.4028/www.scientific.net/amm.376.69.

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The present study deals with the shear behavior of the composite sandwich panels comprised of Polyvinylchloride (PVC) and Polyurethane (PU) foam core sandwiched between Glass Fiber Reinforced Polymer (GFRP) skins using epoxy resin. Experiments have been carried out to characterize the mechanical response of the constituent materials under tension, compression and shear loading. In-plane shear tests for the sandwich panel reveal that the main failure mode is the delamination between the skin and the core rather than shearing the core itself since the skin-core interaction is the weakest link in such structure. The Finite Element Analysis (FEA) of the sandwich structure, based on the non-linear behavior of the foam core and skin-core cohesive interaction, shows that shear response and failure mode can be predicted with high accuracy.

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16

Jackson, K. P., J. M. Allwood y M. Landert. "Incremental Forming of Sandwich Panels". Key Engineering Materials 344 (julio de 2007): 591–98. http://dx.doi.org/10.4028/www.scientific.net/kem.344.591.

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This paper presents a first investigation of the applicability of incremental sheet forming (ISF) to sandwich panels. Two initial tests on various sandwich panel designs established that sandwich panels which are ductile and incompressible are the most suitable for the process. Further tests on a sandwich panel with mild steel face plates and a continuous polypropylene core demonstrated that patterns of deformation and tool forces followed similar trends to a sheet metal. It is concluded that, where mechanically feasible, ISF can be applied to sandwich panels using existing knowledge of sheet metals with the expectation of achieving similar economic benefits. Potentially this will increase the range of applications for which sandwich panels are viable.

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17

Constantin, Nicolae, Marin Sandu, Adriana Sandu, Paulina Spânu, Dorin Roşu y Cătălin Enescu. "Study upon the Damage Tolerance of Thick Sandwich Materials". Solid State Phenomena 266 (octubre de 2017): 287–91. http://dx.doi.org/10.4028/www.scientific.net/ssp.266.287.

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Sandwich composite materials are widely used in various applications, due to their advanced flexibility in responding to special design requirements. This paper presents the evaluation of thick sandwiches, aimed to be imbedded in platforms of a green energy unit, accommodating storage water tanks. The evaluation of the damage tolerance was made having in view previous studies on similar materials and covered assessment of results obtained during low velocity impact tests and post-impact tests, aimed to establish the residual mechanical performance. Ways to increase the damage tolerance, by diminishing the invasive effect of low velocity impact, were also explored.

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18

Andrzejewski, Jacek, Marcin Gronikowski y Joanna Aniśko. "A Novel Manufacturing Concept of LCP Fiber-Reinforced GPET-Based Sandwich Structures with an FDM 3D-Printed Core". Materials 15, n.º 15 (5 de agosto de 2022): 5405. http://dx.doi.org/10.3390/ma15155405.

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The presented research was focused on the development of a new method of sandwich structure manufacturing involving FDM-printing (fused deposition modeling) techniques and compression molding. The presented concept allows for the preparation of thermoplastic-based composites with enhanced mechanical properties. The sample preparation process consists of 3D printing the sandwich’s core structure using the FDM method. For comparison purposes, we used two types of GPET (copolymer of polyethylene terephthalate)-based filaments, pure resin, and carbon fiber (CF)-reinforced filaments. The outer reinforcing layer “skins” of the sandwich structure were prepared from the compression molded prepregs made from the LCP (liquid-crystal polymer)-fiber fabric with the GPET-based matrix. The final product consisting of an FDM-printed core and LCP-based prepreg was prepared using the compression molding method. The prepared samples were subjected to detailed materials analyses, including thermal analyses (thermogravimetry-TGA, differencial scanning calorimetry-DSC, and dynamic thermal-mechanical analysis-DMTA) and mechanical tests (tensile, flexural, and impact). As indicated by the static test results, the modulus and strength of the prepared composites were slightly improved; however, the stiffness of the prepared materials was more related to the presence of the CF-reinforced filament than the presence of the composite prepreg. The main advantage of using the developed method is revealed during impact tests. Due to the presence of long LCP fibers, the prepared sandwich samples are characterized by very high impact resistance. The impact strength increased from 1.7 kJ/m2 for pure GPET samples to 50.4 kJ/m2 for sandwich composites. For GPET/CF samples, the increase is even greater. The advantages of the developed solution were illustrated during puncture tests in which none of the sandwich samples were pierced.

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19

Ha, Giap X., Andreas Bernaschek y Manfred W. Zehn. "Experimentally examining the mechanical behaviour of nap-core sandwich material – A novel type of structural composite". Journal of Reinforced Plastics and Composites 38, n.º 8 (24 de diciembre de 2018): 369–78. http://dx.doi.org/10.1177/0731684418820437.

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Experimental investigation of the nap-core sandwich is presented in detail, in which the nap-core is based on knitted fabric, being impregnated with a thermoset resin, formed to create cup-shaped naps, and stabilized to assume a permanent 3D contour. The material is a novel type of lightweight sandwich-structured composite which has good specific strengths and possesses various properties crucial for engineering applications, but its exploitation is still restricted due to insufficient research and understanding. The sample preparation is first described, being followed by the test implementation and outcomes. The results obtained from typical tests demonstrate high performance of the nap-core sandwich samples under different cases of loading. They also reveal the sandwich’s essential behaviours which are similar to those of a common shell structure, giving it a great potential of being computationally modelled with finite element software.

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20

Zaharia, Sebastian Marian, Mihai Alin Pop, Lucia-Antoneta Chicos, George Razvan Buican, Camil Lancea, Ionut Stelian Pascariu y Valentin-Marian Stamate. "Compression and Bending Properties of Short Carbon Fiber Reinforced Polymers Sandwich Structures Produced via Fused Filament Fabrication Process". Polymers 14, n.º 14 (19 de julio de 2022): 2923. http://dx.doi.org/10.3390/polym14142923.

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Additive manufacturing, through the process of thermoplastic extrusion of filament, allows the manufacture of complex composite sandwich structures in a short time with low costs. This paper presents the design and fabrication by Fused Filament Fabrication (FFF) of composite sandwich structures with short fibers, having three core types C, Z, and H, followed by mechanical performance testing of the structures for compression and bending in three points. Flatwise compression tests and three-point bending have clearly indicated the superior performance of H-core sandwich structures due to dense core structures. The main modes of failure of composite sandwich structures were analyzed microscopically, highlighting core shear buckling in compression tests and face indentation in three-point bending tests. The strength–mass ratio allowed the identification of the structures with the best performances considering the desire to reduce the mass, so: the H-core sandwich structures showed the best results in compression tests and the C-core sandwich structures in three-point bending tests. The feasibility of the FFF process and the three-point bending test of composite wing sections, which will be used on an unmanned aircraft, have also been demonstrated. The finite element analysis showed the distribution of equivalent stresses and reaction forces for the composite wing sections tested for bending, proving to validate the experimental results.

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21

Buican, George Razvan, Sebastian-Marian Zaharia, Mihai Alin Pop, Lucia-Antoneta Chicos, Camil Lancea, Valentin-Marian Stamate y Ionut Stelian Pascariu. "Fabrication and Characterization of Fiber-Reinforced Composite Sandwich Structures Obtained by Fused Filament Fabrication Process". Coatings 11, n.º 5 (19 de mayo de 2021): 601. http://dx.doi.org/10.3390/coatings11050601.

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The application of fused filament fabrication processes is rapidly expanding in many domains such as aerospace, automotive, medical, and energy, mainly due to the flexibility of manufacturing structures with complex geometries in a short time. To improve the mechanical properties of lightweight sandwich structures, the polymer matrix can be strengthened with different materials, such as carbon fibers and glass fibers. In this study, fiber-reinforced composite sandwich structures were fabricated by FFF process and their mechanical properties were characterized. In order to conduct the mechanical tests for three-point bending, tensile strength, and impact behavior, two types of skins were produced from chopped carbon-fiber-reinforced skin using a core reinforced with chopped glass fiber at three infill densities of 100%, 60%, and 20%. Using microscopic analysis, the behavior of the breaking surfaces and the most common defects on fiber-reinforced composite sandwich structures were analyzed. The results of the mechanical tests indicated a significant influence of the filling density in the case of the three-point bending and impact tests. In contrast, the filling density does not decisively influence the structural performance of tensile tests of the fiber-reinforced composite sandwich structures. Composite sandwich structures, manufactured by fused filament fabrication process, were analyzed in terms of strength-to-mass ratio. Finite element analysis of the composite sandwich structures was performed to analyze the bending and tensile behavior.

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22

Reddy, P. Praveen Kumar, Chinmaya Prasad Padhy y P. Janaki Ramulu. "AA5052-PVC-AA5052 (Al-PVC-Al) Sandwich Sheets Forming Analysis through In-Plane Plane Stretching Tests". Scientific World Journal 2024 (8 de marzo de 2024): 1–12. http://dx.doi.org/10.1155/2024/5117746.

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Sheet metal forming is one of the key processes for the automotive sector to be considered. Sheet metal formability is being tested as received, joining them with different welding/joining processes (i.e., tailored blanks) and making them as sandwich forms to reduce the total weight of the body. These sandwich formations of sheets are an advanced method by incorporating PVC/polymer sheets in between metal sheets with a suitable binder. The present work has investigated the formability of AA5052-PVC-AA5052 (Al-PVC-Al) sandwich sheets by considering the sheet rolling direction as a parameter. The mechanical properties of base metal and sandwich sheets were evaluated by conducting the uniaxial tensile tests. For forming behaviour of Al-PVC-Al sandwich sheets, in-plane plane stretching tests were performed on the universal tensile testing machine. From the results, it has been observed that 0-degree and 90-degree rolling direction of AA5052 sheets provided almost similar forming behaviour where the 45-degree rolling direction showed less formability. The limit strains (by which the forming limit curve has been developed and the safe and failure zones are separated) are 0.043, 0.038, and 0.043 of 0°, 45°, and 90°, respectively. Considering 0°-P-90°, 90°-P-90, 0°-P-45°, 0°-P-90°, and 45°-P-45° sandwich sheets with their corresponding limit strains of 0.060, 0.058,0.057, 0.052, and 0.050, a better formability is seen in 0°-P-90° sandwich, followed by 90°-P-90, 0°-P-45°, 0°-P-90°, and 45°-P-45°. The improvement in the formability is calculated as 28.33%, 25.86%, and 24.0% in comparison with the base metal in 0-degree, 90-degree, and 45-degree rolling directions and 0°-P-90°, 90°-P-90, and 45°-P-45° sandwich sheets.

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23

Yoshioka, Hideki, Yoshiki Tanaka, Yuhei Nishio, Takafumi Noguchi, Kyoichi Kobayashi, Yoshifumi Ohmiya, Manabu Kanematsu et al. "Self-standing Compartment Fire Tests on Sandwich Panels". Fire Science and Technology 35, n.º 1 (2016): 19–38. http://dx.doi.org/10.3210/fst.35.19.

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24

Xie, M., N. Foundoukos y J. C. Chapman. "Static tests on steel–concrete–steel sandwich beams". Journal of Constructional Steel Research 63, n.º 6 (junio de 2007): 735–50. http://dx.doi.org/10.1016/j.jcsr.2006.08.001.

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25

Xue, Qi Chao, Guang Ping Zou y Tao Xue. "The Influence of Cycling Frequency to Response Loading in Fatigue Tests for Sandwich Beam with Viscoelastic Core". Key Engineering Materials 577-578 (septiembre de 2013): 665–68. http://dx.doi.org/10.4028/www.scientific.net/kem.577-578.665.

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In 3-point bending fatigue experiments of sandwich plate with visoelastic core and steel faceplates, it is found that response loading of specimen is very sensitive to cycling frequency. From fatigue test, different loading response of sandwich beam obtained in various cycling frequencies. Based on viscoelastic theory, responses of deformation of sandwich plate in cyclic square load wave are calculated. And an explanation of influences of cycling frequency is elaborated.

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26

Zaharia, Sebastian Marian, Larisa Anamaria Enescu y Mihai Alin Pop. "Mechanical Performances of Lightweight Sandwich Structures Produced by Material Extrusion-Based Additive Manufacturing". Polymers 12, n.º 8 (4 de agosto de 2020): 1740. http://dx.doi.org/10.3390/polym12081740.

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Material Extrusion-Based Additive Manufacturing Process (ME-AMP) via Fused Filament Fabrication (FFF) offers a higher geometric flexibility than conventional technologies to fabricate thermoplastic lightweight sandwich structures. This study used polylactic acid/polyhydroxyalkanoate (PLA/PHA) biodegradable material and a 3D printer to manufacture lightweight sandwich structures with honeycomb, diamond-celled and corrugated core shapes as a single part. In this paper, compression, three-point bending and tensile tests were performed to evaluate the performance of lightweight sandwich structures with different core topologies. In addition, the main failure modes of the sandwich structures subjected to mechanical tests were evaluated. The main failure modes that were observed from mechanical tests of the sandwich structure were the following: face yielding, face wrinkling, core/skin debonding. Elasto-plastic finite element analysis allowed predicting the global behavior of the structure and stressing distribution in the elements of lightweight sandwich structures. The comparison between the results of bending experiments and finite element analyses indicated acceptable similarity in terms of failure behavior and force reactions. Finally, the three honeycomb, diamond-celled and corrugated core typologies were used in the leading edge of the wing and were impact tested and the results created favorable premises for using such structures on aircraft models and helicopter blade structures.

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Shahdin, Amir, Joseph Morlier, Laurent Mezeix, Christophe Bouvet y Yves Gourinat. "Evaluation of the Impact Resistance of Various Composite Sandwich Beams by Vibration Tests". Shock and Vibration 18, n.º 6 (2011): 789–805. http://dx.doi.org/10.1155/2011/259295.

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Impact resistance of different types of composite sandwich beams is evaluated by studying vibration response changes (natural frequency and damping ratio). This experimental works will help aerospace structural engineer in assess structural integrity using classification of impact resistance of various composite sandwich beams (entangled carbon and glass fibers, honeycomb and foam cores). Low velocity impacts are done below the barely visible impact damage (BVID) limit in order to detect damage by vibration testing that is hardly visible on the surface. Experimental tests are done using both burst random and sine dwell testing in order to have a better confidence level on the extracted modal parameters. Results show that the entangled sandwich beams have a better resistance against impact as compared to classical core materials.

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Doubrava, Karel y Ctirad Novotný. "Sandwich Roof of the Bus – Fatigue and Strength Tests". Applied Mechanics and Materials 827 (febrero de 2016): 3–6. http://dx.doi.org/10.4028/www.scientific.net/amm.827.3.

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Lightweight and safe roof of the bus was solved within the MIT CR: FR-TI4/349 project. Several variants of sandwich roof were tested on samples in a prior period. Several errors of adhesive joints occurred during the production of the bus roof. Methyl methacrylate adhesive was tested with respect to the declared adhesive ability for arbitrary surfaces. Standardised shear test of the adhesive joints were made for tuning of the numerical model. The obtained parameters are used forthe numerical model of sandwich roof segment. Roof segments were loaded by four points bending and experimentally obtained data were compared with the results of numerical simulations. Several specimens were subjected to cyclic loading in order to get approximate fatigue life of tested variants.

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29

Abdul Rahman, S. Syed y K. S. Satyanarayanan. "Experimental and Numerical Simulation of Effects of High Temperature on RC Frame Infilled with Sandwich Panel". Civil Engineering Journal 10, n.º 1 (1 de enero de 2024): 280–98. http://dx.doi.org/10.28991/cej-2024-010-01-018.

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This study investigated the structural behavior of reinforced concrete (RC) frames infilled with masonry walls and polyurethane (PU) sandwich wall panels at elevated temperatures. This study aims to assess the influence of temperature on the stiffness and load-carrying capacity of infilled frames, optimize the thickness of the sandwich wall panel, and compare the performance of masonry and sandwich infill systems. Analytical investigations were conducted using finite element analysis software (ABAQUS) to simulate the behavior of the frames at elevated temperatures and consider various configurations of skin thickness for PU sandwich panels. Experimental tests were performed to validate the analytical results. The frames were subjected to transient temperature conditions and uniform unit loads to evaluate their response. Experimental tests were conducted on RC frames infilled with masonry and sandwich-wall panels at elevated temperatures. The frames were subjected to static loading, and their deformations and failure modes were observed. The analytical study revealed that an increase in the skin thickness of the sandwich panel improved its temperature resistance, stress-withstanding ability, and displacement. A skin thickness of 0.45 mm was determined to be the optimal choice considering stress levels and economic factors. The infilled frame with the sandwich wall panel exhibited a 19.22% higher initial stiffness than the masonry wall panel in the experimental tests. The ultimate load-carrying capacity decreased by 17.86% in the infilled sandwich wall panel frame compared to the masonry infill system. The study provides valuable insights into the behavior of RC frames infilled with masonry walls and sandwich wall panels under elevated temperatures. The optimized thickness of the PU sandwich panel was determined by balancing the thermal resistance and the structural performance. The infilled frames with sandwich wall panels exhibited enhanced stiffness but slightly reduced ultimate load-carrying capacity compared with the masonry infill. These findings contribute to the understanding of thermal effects on building structures and can aid in the design and construction of more resilient and efficient buildings in the future. Doi: 10.28991/CEJ-2024-010-01-018 Full Text: PDF

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Essassi, Khawla, Jean-Luc Rebiere, Abderrahim El Mahi, Mohamed Amine Ben Souf, Anas Bouguecha y Mohamed Haddar. "Investigation of the Static Behavior and Failure Mechanisms of a 3D Printed Bio-Based Sandwich with Auxetic Core". International Journal of Applied Mechanics 12, n.º 05 (junio de 2020): 2050051. http://dx.doi.org/10.1142/s1758825120500519.

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In this research contribution, the static behavior and failure mechanisms are developed for a three-dimensional (3D) printed dogbone, auxetic structure and sandwich composite using acoustic emissions (AEs). The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid reinforced with micro-flax fibers. Tensile tests are conducted on the skins and the core while bending tests are conducted on the sandwich composite. Those tests are carried out on four different auxetic densities in order to investigate their effect on the mechanical and damage properties of the materials. To monitor the invisible damage and damage propagation, a highly sensitive AE testing method is used. It is found that the sandwich with high core density displays advanced mechanical properties in terms of bending stiffness, shear stiffness, facing bending stress and core shear stress. In addition, the AE data points during testing present an amplitude range of 40–85[Formula: see text]dB that characterizes visible and invisible damage up to failure.

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31

Stanisavljević, Gorjana, Darinka Golubović Matić, Milorad Komnenović, Ivana Vasović Maksimović y Željko Flajs. "Numerical and Experimental Study on Loading Behavior of Facade Sandwich Panels". Buildings 13, n.º 6 (18 de junio de 2023): 1554. http://dx.doi.org/10.3390/buildings13061554.

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This paper focuses on the study of the strength of facade sandwich panels used in building construction. The paper describes the results of experimental and numerical research on the behavior of sandwich panels made of polyisocyanurate core (PIR) and their structural connections when exposed to tensile and compressive loads. In the initial phase of this study, laboratory tests were performed to determine the physical and mechanical characteristics of the material from which the sandwich panels are made. Laboratory tensile and compression tests were performed on small samples of sandwich facade panels. In order to verify the obtained results, they were compared with the numerical analysis performed in the ANSYS software. The numerical model was found to accurately predict the results of the laboratory tests, suggesting that the model can be used to predict the behavior of these panels under different loads in service. The study showed that the foam core sandwich panel exhibits excellent mechanical properties. The results indicate the suitability of foam-based composite structures in the construction industry for various applications, such as roof and wall structures. The findings of this study may help in the development of lightweight and durable construction materials for the industry.

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32

Wang, Bo, Yunfeng Shi, Caihua Zhou y Tong Li. "Failure mechanism of PMI foam core sandwich beam in bending". International Journal for Simulation and Multidisciplinary Design Optimization 6 (2015): A8. http://dx.doi.org/10.1051/smdo/2015008.

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Polymethacrylimide (PMI) foams have been widely applied in aerospace engineering as the core material of sandwich structures. This paper proposes a modified model to predict the constitutive relation of PMI foams and compares it to existing testing data. The study is then applied to the investigation of the failure mechanism of PMI foam core sandwich beams in bending. Corresponding bending tests were carried out where a complex failure process was observed through a high-speed camera. Numerical model of the foregoing sandwich beam is developed, in which the maximum principal stress criteria is used to predict damage propagation in PMI foam core. Both results from tests and numerical simulation validate the reliability of the theoretical prediction of the failure of PMI foam core sandwich beam using the proposed modified model of PMI foams. This study provides a theoretic tool for the design of sandwich structures with PMI foam core.

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33

Rodrigues, Marlon Bender Bueno, Ronan Côrrea, Pedro Henrique G. De Cademartori, Ana C. R. Ribeiro, Rodrigo Coldebella, Rafael A. Delucis, Nayara Lunkes y André L. Missio. "Bio-Based Tannin Foams: Comparing Their Physical and Thermal Response to Polyurethane Foams in Lightweight Sandwich Panels". Compounds 4, n.º 1 (25 de diciembre de 2023): 1–16. http://dx.doi.org/10.3390/compounds4010001.

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Rigid polyurethane foams are the better-performing material for the most common insulation purposes, like sandwich panels. Nevertheless, they are highly flammable materials, release toxic gases, and are manufactured from fossil sources. As an alternative, tannin foams are bio-based materials that work as innovative alternatives thanks to their great fire resistance, as well as lower smoke and harmful gases emissions. In the present study, lab-made foams of both materials were compared through morphology, thermal and fire degradation, mechanical properties, and water affinity in order to fill the technological gap between them and their related sandwich panels. It was observed that tannin foams are still relatively inhomogeneous (since formaldehyde was not used) and present a high affinity for water but have higher thermal and fire resistance. The flat compression strength of the polyurethane sandwiches was greater than that of tannin sandwiches (3.61 and 3.09 MPa, respectively) thanks, mainly, to the crosslinking degree difference between the resins. Also, tannin foams presented a lower weight loss (−70.684% lower weight loss in flammability tests than polyurethane foams) and the ability to self-extinguish the flame. Therefore, sandwich panels with tannin foam cores could be successful materials in areas that require protection against fire, such as the building engineering and automotive industries.

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Reis, Paulo N. B., Carlos A. C. P. Coelho y Fábio V. P. Navalho. "Impact Response of Composite Sandwich Cylindrical Shells". Applied Sciences 11, n.º 22 (19 de noviembre de 2021): 10958. http://dx.doi.org/10.3390/app112210958.

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Nowadays, due to the complexity and design of many advanced structures, cylindrical shells are starting to have numerous applications. Therefore, the main goal of this work is to study the effect of thickness and the benefits of a carbon composite sandwich cylindrical shell incorporating a cork core, compared to a conventional carbon composite cylindrical shell, in terms of the static and impact performances. For this purpose, static and impact tests were carried out with the samples freely supported on curved edges, while straight edges were bi-supported. A significant effect of the thickness on static properties and impact performance was observed. Compared to thinner shells, the failure load on the static tests increased by 237.9% and stiffness by 217.2% for thicker shells, while the restored energy obtained from the impact tests abruptly increased due to the collapse that occurred for the thinner ones. Regarding the sandwich shells, the incorporation of a cork core proved to be beneficial because it promoted an increase in the restored energy of around 44.8% relative to the conventional composite shell. Finally, when a carbon skin is replaced by a Kevlar one (hybridization effect), an improvement in the restored energy of about 20.8% was found. Therefore, it is possible to conclude that numerous industrial applications can benefit from cylindrical sandwiches incorporating cork, and their hybridization with Kevlar fibres should be especially considered when they are subject to impact loads. This optimized lay-up is suggested because Kevlar fibres fail through a series of small fibril failures, while carbon fibres exhibit a brittle collapse.

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35

Zha, Xiao Xiong, Pei Cheng Qin y Hong Xin Wang. "Experiment and Finite Element Study on the Structural Behavior of Steel Sandwich Panels". Advanced Materials Research 168-170 (diciembre de 2010): 1051–54. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1051.

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This work try to deal with the analysis of a class of sandwich panels widely employed in engineering constructions. In order to study its structure behavior, a systematic experimental study on both roof and wall sandwich panels filled with Polyurethane foam (PU) under uniformly distributed load is conducted. Informed by the tests, appropriate finite element models are developed to model the tests.

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36

Uzay, Çağrı y Necdet Geren. "Effect of stainless-steel wire mesh embedded into fibre-reinforced polymer facings on flexural characteristics of sandwich structures". Journal of Reinforced Plastics and Composites 39, n.º 15-16 (5 de mayo de 2020): 613–33. http://dx.doi.org/10.1177/0731684420921952.

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In this study, flexural characteristics of low-density polyvinylchloride foam core sandwich structures consist of carbon fibre/epoxy facings hybridised with very thin stainless-steel wire mesh sheets were investigated. A comprehensive work was conducted considering the following design parameters: core thicknesses, wire mesh sizes, stacking sequences of wire mesh sheets and support span lengths for flexural tests. During the evaluation of flexural characteristics, experimental ASTM standards (C393, D3039, D7249 and D7250) were utilised. In addition, experimental flexural stiffness values were compared to analytically obtained results. By hybridisation of carbon fibre/epoxy facings with wire mesh sheets, significant improvements in flexural characteristics of sandwich structures were obtained. Besides improving bending behaviour and the larger amount of load-carrying capacity even at the same deflection values, the sandwiches with wire mesh sheets also prevented catastrophic sudden failure, which is the common case for carbon/epoxy/polymer foam core sandwiches. Response surface methodology was applied to evaluate the effects of the design variables on the load capacity of the sandwiches, and optimal solutions were revealed. The developed sandwiches can be good candidates in applications where both high stiffness-to-weight ratio and resistance to sudden failure are desired.

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37

Nikbakht, Ehsan, Mahmoud Gad y Jia Wei Chang. "Push-out tests on steel composite sections with engineered cementitious composite". Engineering Solid Mechanics 12, n.º 1 (2024): 11–16. http://dx.doi.org/10.5267/j.esm.2023.7.007.

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This paper investigates the shear strength and failure modes of steel-concrete-steel (SCS) sandwich composite member with Engineered Cementitious Concrete (ECC) and explores the influences of various shear connectors such as headed stud and bolt on shear behavior of SCS sandwich composite member by carrying out push-out testing program. Based on the test results in this study, the failure modes and the load-slip behavior of the specimens are investigated. In addition, the experimental results on the shear resistance of the headed stud connector with various connector spacing and numbers of connector is compared and explored.

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38

Johnson-Groh, Mara. "Raman scattering technique allows for quick and accurate COVID-19 tests". Scilight 2023, n.º 2 (13 de enero de 2023): 021102. http://dx.doi.org/10.1063/10.0016905.

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39

Seno, Aldyandra Hami, Eko Koswara, Hendri Syamsudin y Djarot Widagdo. "Analysis of Bending Loads on Bamboo-Balsa and Bamboo-Polypropylene Honeycomb Composite Sandwiches". Advanced Materials Research 1125 (octubre de 2015): 94–99. http://dx.doi.org/10.4028/www.scientific.net/amr.1125.94.

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This research was done to evaluate the bending behavior (load-deflection curve and failuremode) of sandwich structures using Tali Bamboo strips as sandwich skin material. Bending tests wereconducted on sandwich specimens with end grain balsa (3-point bending) and polypropylene (PP)honeycomb cores (4-point bending) to evaluate their bending behavior. From the test results,analytical and numerical models were developed to simulate the observed bending behavior. Themodels are able to simulate the pre-failure bending behavior and failure modes (core shear failure) ofthe specimens. It is also shown that for thin (length/thickness > 20) sandwiches the models are moreaccurate since shear effects are less prominent. With the obtained models a predictive comparison isdone between the PP and balsa cored specimens since the testing configuration for each type wasdifferent. The analysis results show that balsa cored specimens are able to withstand higher transversebending loads due to the higher shear strength of the balsa core. These prediction results are to beproven by specimen testing which is the subject of future research.

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40

Crupi, Vincenzo, Emre Kara, Gabriella Epasto, Eugenio Guglielmino y Halil Aykul. "Theoretical and experimental analysis for the impact response of glass fibre reinforced aluminium honeycomb sandwiches". Journal of Sandwich Structures & Materials 20, n.º 1 (8 de febrero de 2016): 42–69. http://dx.doi.org/10.1177/1099636216629375.

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Honeycomb sandwich structures are increasingly used in the automotive, aerospace and shipbuilding industries where fuel savings, increase in load carrying capacity, vehicle safety and decrease in gas emissions are very important aspects. The aim of this study was to develop the theoretical methods, initially proposed by the authors and by other researchers for the prediction of low-velocity impact responses of sandwich structures. The developed methods were applied to sandwich structures with aluminium honeycomb cores and glass-epoxy facings for the assessment of impact parameters and for the prediction of limit loads. The values of model parameters were compared with data reported in literature and the predictions of the limit loads were validated by means of the experimental data. Good achievement was obtained between the results of the theoretical models and the experimental data. The failure mode and the internal damage of the sandwich panels have been investigated using 3D computed tomography, which allowed the evaluation of parameters of energy balance model, and infrared thermography, which allowed the detection of the temperature evolution of the specimens during the tests. The experimental and theoretical results demonstrated that the use of glass-epoxy reinforcement on aluminium honeycomb sandwiches enhances the energy absorption and load carrying capacities.

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41

Sun, Shiyong, Xinling Wang, Jianping Liang, Rui Yang y Yanguang Zhao. "Analysis on fracture behaviour of stitched foam sandwich composites using interlaminar tension test". Journal of Sandwich Structures & Materials 24, n.º 3 (27 de diciembre de 2021): 1515–34. http://dx.doi.org/10.1177/10996362211063154.

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Sandwich composites are susceptible to interfacial delamination, owing to the mismatches in the material properties between the face sheets and core. Previous studies have shown that stitching can improve the performance of sandwich composites. In this study, an analysis approach was developed to investigate the fracture behaviour of stitched foam sandwich composites. The stitched foam sandwich composites were manufactured by a vacuum-assisted resin transfer moulding process. Interlaminar tension tests revealed the effects of the linear thread density on the failure mechanisms of the stitched foam sandwich composites. Asymmetric double cantilever beam tests were performed to investigate the influences of the stitch thread reinforcement on the fracture behaviour. An analytical approach combining extended finite element method and nonlinear spring elements was proposed to predict the failure behaviour of the stitched sandwich composites. Experiment and simulation approaches were employed to investigate the influences of the stitch parameters (stitch pitch and linear thread density) on the ultimate load and energy absorption. The results show that stitched method can significantly enhance the mechanical properties of sandwich composites. The energy absorption and ultimate load values of the specimens tend to increase with an increase in the linear thread density or a decrease in the stitch pitch.

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42

Xie, Zong Hong, Qun Yan, Jiang Tian y Xiao Yu Liu. "Quasi-Static Indentation Test on Composite Sandwich Panels with Foam Core". Advanced Materials Research 718-720 (julio de 2013): 214–18. http://dx.doi.org/10.4028/www.scientific.net/amr.718-720.214.

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In accordance to ASTM test standards, this paper presents experimental studies on quasi-static indentation tests on sandwich panels with carbon fiber reinforced facesheet and foam core. The indentation force vs. displacement curves were obtained. A series of tests with different indentation depth were carried out to study the damage modes and damage propagation process of foam core sandwich panels under quasistatic indentation force.

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43

Fan, Xue Mei, Jian Feng Wang, Cheng Jin Duan, Xiang Xin Xia y Zhao Hui Wang. "Study on Automobile Body Performance of Honeycomb Sandwich Composite Material". Advanced Materials Research 567 (septiembre de 2012): 146–49. http://dx.doi.org/10.4028/www.scientific.net/amr.567.146.

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In order to analyze the mechanical properties of Carbon/epoxy facings-Aluminum honeycomb sandwich structure, we simulated panels of different layers and core thickness using ABAQUS finite element analysis program. And three-point bending tests and shear tests were made on the same panels using electronic universal testing machine. In addition, we also made the same three-point bending tests on steel tubes to get a comparison with honeycomb sandwich panels. It could be seen that, the simulated results were basically identified with experimental results. The results indicated that core thickness played an important role in the panels’ bulking modulus, and number of carbon fiber layers decided the shear strength. As a whole, honeycomb sandwich structure was suitable for use in the car body with good mechanical properties under premise of lighter.

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44

Bělský, Petr y Martin Kadlec. "Capability of non-destructive techniques in evaluating damage to composite sandwich structures". International Journal of Structural Integrity 10, n.º 3 (10 de junio de 2019): 356–70. http://dx.doi.org/10.1108/ijsi-10-2018-0067.

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Purpose Defects can be caused by a number of factors, such as maintenance damage, ground handling and foreign objects thrown up from runways during an in-service use of composite aerospace structures. Sandwich structures are capable of absorbing large amounts of energy under impact loads, resulting in high structural crashworthiness. This situation is one of the many reasons why sandwich structures are extensively used in many aerospace applications nowadays. Their non-destructive inspection is often more complex. Hence, the choice of a suitable non-destructive testing (NDT) method can play a key role in successful damage detection. The paper aims to discuss these issues. Design/methodology/approach A comparison of detection capabilities of selected C-scan NDT methods applicable for inspections of sandwich structures was performed using water-squirt, air-coupled and pitch-catch (PC) ultrasonic techniques, supplemented by laser shearography (LS). Findings Test results showed that the water-squirt and PC techniques are the most suitable methods for core damage evaluation. Meanwhile, the air-coupled method showed lower sensitivity for the detection of several artificial defects and impact damage in honeycomb sandwiches when unfocussed transducers were used. LS can detect most of the defects in the panels, but it has lower sensitivity and resolution for honeycomb core-type sandwiches. Originality/value This study quantitatively compared the damage size indication capabilities of sandwich structures by using various NDT techniques. Results of the realised tests can be used for successful selection of a suitable NDT method. Combinations of the presented methods revealed most defects.

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45

Rupp, Peter, Peter Elsner y Kay A. Weidenmann. "Specific bending stiffness of in-mould-assembled hybrid sandwich structures with carbon fibre reinforced polymer face sheets and aluminium foam cores manufactured by a polyurethane-spraying process". Journal of Sandwich Structures & Materials 21, n.º 8 (13 de agosto de 2017): 2779–800. http://dx.doi.org/10.1177/1099636217725250.

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In this paper, the bending stiffness-to-weight-ratio of novel hybrid sandwich structures is investigated. The build-up of the sandwich panels consisted of face sheets made from carbon fibre reinforced polymer, aluminium foam cores and an interface of foamed polyurethane. The sandwich panels were produced in a single step, infiltrating the face sheet fibres and connecting the face sheets to the core simultaneously. By means of mechanical characterization, specimens with several variations of face sheet architecture and thickness, core structure and interface properties were examined. Quasi-static four-point bending and flatwise compression tests of the sandwich composites were conducted, as well as tensile tests of the face sheets. The results of the tensile and compressive tests were integrated in analytical models, describing the sandwich stiffness depending on the load case and the face sheet volume fraction. The effective Young’s modulus of the composite, measured in the four-point bending test, correlates well to the modelled effective bending modulus calculated from the single components face sheet and core. The model underestimates the effective density of the bending specimens. It could be shown that this underestimation results from the polyurethane foam connecting the face sheets to the core, as the mass of this polyurethane is not included in the model.

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46

Pavlova, S. A. "Analysis of contact interaction of polymer honeycomb core and CFRP base layers in sandwich-core constructions". VESTNIK of Samara University. Aerospace and Mechanical Engineering 20, n.º 1 (20 de abril de 2021): 87–96. http://dx.doi.org/10.18287/2541-7533-2021-20-1-87-96.

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The article considers the challenge of studying the mechanical properties of composite sandwich constructions at the interface between the base layers and the lightweight core. The results of strength tests are presented for specimens of sandwich-core panels with coats made of high-strength carbon fiber-reinforced plastics (CFRP) and polymer honeycomb core considering various loading conditions. It is noted that a discrepancy in the values of shear stresses occurs in four-point bending and shear tests due to the complex stress-strain state of the specimens during bending. In order to interpret the experimental data, numerical analysis of the area of contact interaction between the coats and the filler of the sandwich-core composite structures is carried out. It is noted that in the presence of significant normal stresses in the adhesive coat the base layers separate from the core during shear tests and there is underestimation of the values of shear stresses by about 20%. Recommendations for the assignment of ultimate shear stresses for the use in practical design of sandwich-core composite constructions are put forward.

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47

Arslan, Kemal, Recep Gunes, M. Kemal Apalak y JN Reddy. "Experimental tests and numerical modeling of ballistic impact on honeycomb sandwich structures reinforced by functionally graded plates". Journal of Composite Materials 51, n.º 29 (8 de marzo de 2017): 4009–28. http://dx.doi.org/10.1177/0021998317695423.

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The aim of this study is to determine the ballistic impact response of a novel sandwich structure consisting of aluminum honeycomb and Al/SiC functionally graded face sheets and develop a compatible numerical model with experiments. The experiments were carried out by a single-stage gas gun system and numerical simulations were performed using the explicit finite element code, LS-DYNA®. The mechanical properties of the functionally graded face sheets through the thickness were considered in accordance with a power-law distribution. The Mori–Tanaka scheme was used in order to determine the effective material properties of the functionally graded face sheets at a local point. In order to simulate the elastoplastic behavior of the functionally graded face sheets, Tamura–Tomota–Ozawa model was implemented in the numerical model. The ballistic performance of the sandwich structure was investigated for metal-rich ( n = 0.1), linear ( n = 1.0), and ceramic-rich ( n = 10.0) compositions of the functionally graded face sheets. The results indicated that the ceramic fraction of the functionally graded face sheets was quite influential on energy absorption capability, damage mechanism, and impact resistance of the sandwich structure. The sandwich structure with linear functionally graded face sheets showed the highest ballistic performance in terms of damage and deformation shapes of the entire sandwich structure among investigated material compositions.

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48

He, Jian, Dongyuan Xie, Qichao Xue y Yangyang Zhan. "Seawater effects on static loads and interlayer cracking performance for polyvinyl chloride foam-cored sandwich composites". Advances in Mechanical Engineering 10, n.º 11 (noviembre de 2018): 168781401880734. http://dx.doi.org/10.1177/1687814018807342.

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The diffusion influence of seawater on the static and interlayer cracking properties of a polyvinyl chloride foam sandwich structure is investigated in this study. After soaking specimens in seawater for various durations, various comparison tests are performed to investigate the effects of seawater. Compression tests for H60 and H200 polyvinyl chloride foam specimens are conducted to study strength and modulus degradation, and the results show that immerging time and temperature have significant effects on polyvinyl chloride foam properties. Tensile tests for glass-fibre-reinforced plastic panels, four-point bending tests and double cantilever bending tests for polyvinyl chloride foam sandwich specimens are also performed. The results show that seawater immerging treatment has a noticeable influence on glass-fibre-reinforced plastic tensile properties and interlayer critical energy release rate values, but has almost no effect on bending properties of foam sandwich specimen. Furthermore, a rate-dependent phenomenon is observed in double cantilever bending tests, in which higher loading rate will lead to larger critical energy release values. Numerical simulation is also performed to illustrate the cracking process of double cantilever bending tests and shows a certain accuracy. The simulation also demonstrates that the viscoelasticity of foam material after immerging treatment results in the rate-dependent characterization of double cantilever bending tests.

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49

Gara, Fabrizio, Laura Ragni, Davide Roia y Luigino Dezi. "Experimental tests and numerical modelling of wall sandwich panels". Engineering Structures 37 (abril de 2012): 193–204. http://dx.doi.org/10.1016/j.engstruct.2011.12.027.

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50

Ruan, Dong, Guoxing Lu y Yat Choy Wong. "Quasi-static indentation tests on aluminium foam sandwich panels". Composite Structures 92, n.º 9 (agosto de 2010): 2039–46. http://dx.doi.org/10.1016/j.compstruct.2009.11.014.

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