Journal articles: 'Composite Sandwich Structures'

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Kausar, Ayesha, Ishaq Ahmad, Sobia A. Rakha, M. H. Eisa, and Abdoulaye Diallo. "State-Of-The-Art of Sandwich Composite Structures: Manufacturing—to—High Performance Applications." Journal of Composites Science 7, no. 3 (March 7, 2023): 102. http://dx.doi.org/10.3390/jcs7030102.

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This cutting-edge review highlights the fundamentals, design, and manufacturing strategies used for sandwich composites. Sandwich composite structures have the advantages of light weight, high strength, impact resistance, stability, and other superior features for advanced applications. In this regard, different core materials have been used in the sandwich composite structures, such as cellular polymer foam, metallic foam, honeycomb, balsa, tubular, and other core geometries. Among these, honeycomb sandwich composite materials have been effectively applied in space engineering, marine engineering, and construction applications. The foremost manufacturing techniques used for sandwiched composite structures include hand lay-up, press method, prepreg method, vacuum bagging/autoclave, vacuum assisted resin infusion, resin transfer molding, compression molding, pultrusion, three-dimensional (3D) printing, four-dimensional (4D) printing, etc. In advanced composite manufacturing, autoclave processes have been the method of choice for the aerospace industry due to less delamination between plies and easy control of thickness dimensions. Moreover, machining processes used for sandwich composites are discussed in this article. In addition to aerospace, the high-performance significance of sandwiched composite structures is covered mainly in relation to automobile engineering and energy absorption applications. The structure-, fabrication-, and application-related challenges and probable future research directions are also discussed in this article.

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Grünewald, Jonas, Patricia Parlevliet, and Volker Altstädt. "Manufacturing of thermoplastic composite sandwich structures." Journal of Thermoplastic Composite Materials 30, no. 4 (August 5, 2016): 437–64. http://dx.doi.org/10.1177/0892705715604681.

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Composite sandwich structures show promising lightweight properties for the aviation industry. Nowadays time-consuming manufacturing methods still prevent an extensive application of composite sandwiches, which can be overcome by the use of thermoplastic polymers in skins and core. During manufacturing of thermoplastic composite (TPC) sandwich structures, the joining of skins and core is a critical step. Therefore, several skin–core joining methods have been under investigation and development in the published literature, which can be categorized into adhesive bonding or fusion bonding. Fusion bonding by means of vacuum moulding, compression moulding or in situ foaming shows great potential for joining sandwich skins and core. Although various phenomena such as core collapsing or skin deconsolidation challenge the processes. This article aims to present an overview of research that has been done in the area of manufacturing TPC sandwich structures and will serve as a baseline and aid for further research and development efforts.

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Ashraf, W., M. R. Ishak, M. Y. M. Zuhri, N. Yidris, and A. M. Ya’acob. "Experimental Investigation on the Mechanical Properties of a Sandwich Structure Made of Flax/Glass Hybrid Composite Facesheet and Honeycomb Core." International Journal of Polymer Science 2021 (March 10, 2021): 1–10. http://dx.doi.org/10.1155/2021/8855952.

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This research is aimed at developing the sandwich structure with a hybrid composite facesheet and investigate its mechanical properties (tensile, edgewise compression, and flexural). The combination of renewable and synthetic materials appears to reduce the weight, cost, and environmental impact compared to pure synthetic materials. The hybrid composite facesheets were fabricated with different ratios and stacking sequence of flax and glass fibers. The nonhybrid flax and glass composite facesheet sandwich structures were fabricated for comparison. The overall mechanical performance of the sandwich structures was improved by increasing the glass fiber ratio in the hybrid composites. The experimental tensile properties of the hybrid facesheet and the edgewise compression strength and ultimate flexural facing stress of the hybrid composites sandwich structures were achieved higher when the results were normalized to the same fiber volume fraction of glass composite. The hybrid composite sandwich structure showed improved compression and flexural facing stress up to 68% and 75%, respectively, compared to nonhybrid flax composites. The hybrid composite using glass in the outer layer achieved the similar flexural stiffness of the nonhybrid glass composite with only a 6% higher thickness than the glass composite sandwich structure.

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Emi Nor Ain Mohammad, Nurul, Aidah Jumahat, and Mohamad Fashan Ghazali. "Impact Properties of Aluminum Foam – Nanosilica Filled Basalt Fiber Reinforced Polymer Sandwich Composites." International Journal of Engineering & Technology 7, no. 3.11 (July 21, 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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Sahu, Santosh Kumar, P. S. Rama Sreekanth, and S. V. Kota Reddy. "A Brief Review on Advanced Sandwich Structures with Customized Design Core and Composite Face Sheet." Polymers 14, no. 20 (October 11, 2022): 4267. http://dx.doi.org/10.3390/polym14204267.

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Sandwich structures are a class of multifunctional high-performance structural composites that have the advantages of being lightweight, of a high strength-to-weight ratio, and of high specific energy absorption capabilities. The creative design of the core along with the apposite material selection for the fabrication of the face sheet and core are the two prerequisites with encouraging areas for further expedition towards the fabrication of advanced composite sandwich structures. The current review work focused on different types of core designs, such as truss, foam, corrugated, honeycomb, derivative, hybrid, hollow, hierarchical, gradient, folded, and smart core along with different composite materials accessible for face sheet fabrication, including fiber-reinforced composite, metal matrix composite, and polymer matrix composite are considered. The joining method plays a major role for the performance evolution of sandwich structures, which were also investigated. Further discussions are aligned to address major challenges in the fabrication of sandwich structures and further enlighten the future direction of the advanced composite sandwich structure. Finally, the work is summarized with a brief conclusion. This review article provides wider guidelines for researchers in designing and manufacturing next-generation lightweight multilayer core sandwich structures.

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Beznea, Elena Felicia, Ionel Chirica, Nicusor Baroiu, and Virgil Teodor. "Parametric Study of Experimental and Numerical Simulation of Sandwich Composite Structures Flexural Behaviour." Materiale Plastice 54, no. 4 (December 30, 2017): 682–88. http://dx.doi.org/10.37358/mp.17.4.4925.

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Sandwich panels with composite/steel skin sheets and foam core are very often used as lightweight structures in automotive, maritime and aerospace applications due to their performances like high bending stiffness and strength and also lightweight. As an alternative to classical structural reinforced panels, the sandwich structures are justifying their use in various industrial fields, making these structures less complex, by eliminating the need for secondary stiffening. In the paper are presented three models of sandwich, steel-foam-steel, composite-foam-composite or steel-foam-composite structures, of different thicknesses, with functional use in various fields depending on necessities. The mechanical characteristics of the materials used in their manufacture have been determined. The panels have been subjected to various load cases in order to determine an optimal combination of weight and strength. At the same time, the numerical models used in the finite element analysis of the sandwich structures with specific elements for layered composites or sandwich (SHELL 4L and SOLID L) are presented.

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Grünewald, Jonas, Tilman Orth, Patricia Parlevliet, and Volker Altstädt. "Modified foam cores for full thermoplastic composite sandwich structures." Journal of Sandwich Structures & Materials 21, no. 3 (June 22, 2017): 1150–66. http://dx.doi.org/10.1177/1099636217708741.

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Full thermoplastic composite sandwich structures with a foam core offer the possibility to be manufactured by fusion bonding in significant shorter cycle times than thermoset-based sandwiches. However, the application of foam cores results in lower mechanical properties such as compression and shear strength compared to honeycomb cores, therefore foam-based sandwiches cannot compete with sandwich structures based on Aramid/phenolic honeycomb cores, the current state of the art. In order to improve the mechanical performance of foam core-based sandwiches while maintaining their advantages, concepts to reinforce the foams were developed in this study. By introducing rods either orthogonally or diagonally to the skin plane, which are fusion bonded to the skins during processing, the compression and shear properties can be improved by up to 1000% and 72%, respectively. Even when correcting for the weight increase, an improved specific compression strength could be achieved. And therefore, the pinning looks especially promising when only applied locally in highly loaded areas for example.

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Mataram, Agung, and Narwi Panggar Besi. "Effect of Thickness Layer of Kenaf Fibre Reinfoeced Fibre Glass, Against Impact of Hybrid Composite Sandwich with Core Sengon." Journal of Mechanical Science and Engineering 6, no. 1 (July 7, 2020): 013–17. http://dx.doi.org/10.36706/jmse.v6i1.30.

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The purpose of this research is to know the impact strength of composite structures of sengon laut sawdust. Experimental results show that the impact toughness of sandwich composite will increase as the thickness of composite sandwich skin increases. The impact failure is due mostly to the shear failure of the core. Brittle specimen failure occurs on the sandwich composites structured with skin and core manufactured with the same thickness of 5 mm. This brittle sandwich composite has a flat cross section on both sides of the fault. The shear failure of the cores occurs in samples with 2 mm thick, 3 mm, 4 mm thick, and 10 mm thick core. In some samples, the shear failure of the cores is accompanied by cracks on the core so that the sandwich composite is broken in several parts. The highest value of absorption energy and the highest impact strength is found on thick composite sandwich variation of 10 mm thick with 4 mm thickness of 2,7860 J and 0,01032 J/mm2.

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Chun, Heoung Jae, and Hyun Su Shin. "Effect of Anisotropic Characteristics of Composite Skins on the Electromagnetic Wave Propagation in the Foam Core Sandwich Structures." International Journal of Modern Physics B 17, no. 08n09 (April 10, 2003): 1782–87. http://dx.doi.org/10.1142/s0217979203019666.

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The propagation of electromagnetic waves in the foam core sandwich structures is highly affected by anisotropic permittivity and loss tangent of composite skins. Even though many investigations were focused on the propagation of electromagnetic waves in the composite materials in last several decades, little investigations were carried out to understand adequately the propagation of the electromagnetic waves in the foam core sandwich structures. In this study, the transmittance of the arbitrary linearly polarized incident TEM waves through the solid composite laminate with various stacking sequences and foam core sandwich structures with composite skins was calculated as functions of fiber orientation of composites and incident angle of the wave by the analytical model.

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Fergusson, Alexander D., Amit Puri, Andrew Morris, and John P. Dear. "Flexural Testing of Composite Sandwich Structures with Digital Speckle Photogrammetry." Applied Mechanics and Materials 5-6 (October 2006): 135–44. http://dx.doi.org/10.4028/www.scientific.net/amm.5-6.135.

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Composite sandwich structures are finding increasingly widespread use in fields ranging from aerospace and wind turbines to sports applications such as skis and surfboards. The high specific stiffness that composite sandwich structures can provide lends them well to these applications. However, the operational environment of these structures is frequently aggressive and often results in damage during service. The extent and effect of damage incurred is an important factor in the design and maintenance of composite sandwich structures. Failure of an individual component can be catastrophic for the rest of the structure. The purpose of this investigation was, firstly, to ascertain whether DSP was a viable technique for determining strain fields within composite sandwich structures. Secondly, to determine whether four point flexure would give rise to pure flexure between the central rollers, and if not, to understand what load conditions were present. This investigation was also carried out with a view to extend the investigation into the effect of defects on composite sandwich structures manufactured by RIFT. The grounds for selection of composite sandwich structures normally lie in their flexural performance. Reliable and accurate quantitative testing methods for evaluating the flexural performance of sandwich panels are needed if composite sandwich structures are to be used safely and effectively. In addition, methods to determine the effect of damage and defects on flexural behaviour of sandwich structures is particularly important for designing the repair and maintenance regimes of composite sandwich components.

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Williams, H. R., R. S. Trask, and I. P. Bond. "Self-healing composite sandwich structures." Smart Materials and Structures 16, no. 4 (June 29, 2007): 1198–207. http://dx.doi.org/10.1088/0964-1726/16/4/031.

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Aravindh, K., D. S. Robinson Smart, Chandrasekar Raja, and M. Ramachandran. "Detection of Composites and Sandwich Structures for Aeronautic Application." Journal on Applied and Chemical Physics 2, no. 1 (May 1, 2023): 20–30. http://dx.doi.org/10.46632/jacp/2/1/3.

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"An overview of sandwich structures in aviation applications is provided in this article. It emphasizes the complexity of designing these structures and addresses the main issues that designers face while working with them. Beginning with early instances from the 1930s and focusing on their significant development during World War II, the article examines the evolution of sandwich structures. It explores their wide range of uses in both civil and military spheres. The article also investigates the impact of polymer materials and sheet technology on the mechanical characteristics of composite sandwich constructions. The essay covers three different types of sandwich structures that were created using manual lay-up, press technique, and autoclave application manufacturing processes. These sandwich specimens underwent impact load tests to determine their failure properties. The structural analysis focused on sandwich panels produced in a similar manner, with an adhesive layer between the cores. The goal of the study was to generate research findings about the effects of stress during sandwich panel fabrication on several mechanical properties of structured sandwich composites, including flexural strength, impact strength, and compressive strength.

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Hanafi, Irvan Nur, Lilies Esthi Riyanti, and Hari Kurniawanto. "DESIGN PROCEDURE FOR MAKING AND REPAIRING COMPOSITE SANDWICH BASED ON AUGMENTED REALITY." EDUTECH 21, no. 3 (December 5, 2022): 240–52. http://dx.doi.org/10.17509/e.v21i3.42697.

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Composite-based structures are becoming increasingly common in aircraft construction. Its use is done to improve structural strength performance and weight loss of aircraft. Composite is divided into two manufacturing concepts, namely, composite sandwich and also composite laminate. The composite sandwich concept provides a method for obtaining high bending stiffness with minimal weight compared to laminate construction. The number of advantages obtained in composite sandwiches can’t be separated from the level of difficulty possessed in the process of making and repairing composites. This study examines the hazards caused in the manufacturing and repair procedures using the Job Hazard Analysis method. The concept and design of the procedure after analysis will be implemented into an augmented reality-based education system using blender and unity applications.Struktur berbahan dasar composite menjadi semakin umum penggunaannya dalam konstruksi pesawat udara. Penggunaanya dilakukan untuk meningkatkan performa kekuatan struktur dan penurunan berat dari pesawat udara. Composite dibagi menjadi dua konsep pembuatan yaitu, sandwich composite dan juga composite laminasi. Konsep sandwich composite menyediakan metode untuk mendapatkan kekakuan lentur tinggi dengan berat minimal dibandingkan dengan konstruksi laminasi. Banyaknya kelebihan yang didapatkan dalam sandwich composite tidak lepas dari tingkat kesulitan yang dimiliki dalam proses pembuatan dan perbaikan composite. Studi ini meneliti bahaya yang disebabkan dalam prosedur pembuatan dan perbaikan menggunakan metode Analisis Bahaya Pekerjaan. Konsep dan desain prosedur setelah dianalisis akan di implementasikan menjadi sebuah sistem edukasi berbasis augmented reality menggunakan aplikasi Blender dan Unity.

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Alshahrani, Hassan, Azzam Ahmed, Hashim Kabrein, and V. R. Arun Prakash. "Mechanical Properties Study on Sandwich Composites of Glass Fiber Reinforced Plastics (GFRP) Using Liquid Thermoplastic Resin, Elium®: Preliminary Experiments." Coatings 12, no. 10 (September 28, 2022): 1423. http://dx.doi.org/10.3390/coatings12101423.

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Composite sandwich structures have been used in high performance applications such as wind turbine blades, due to their unique lightweight structure and superior mechanical properties. In the current study, a new liquid thermoplastic and thermoset resin were used to fabricate four different composite sandwich panels with two various foam types and densities. Composites made with epoxy resin are presented to comprehensively compare the mechanical properties of sandwich structures to elium resin. In the case of the mechanical properties and due to a new liquid thermoplastic resin, extensive comparisons of three-point bending, climbing drum peel, and flatwise tensile strength were investigated and compared with each other. The flexural and flatwise strength of sandwich composite increased by 53% and 75%, respectively, when using Elium resin. Then, the highest value was shown in the GF/PVC/ELIUM structure. The results revealed that Elium resin could be excellent in the case of mechanical properties to replace traditional resins to fabricate various composite structures and manage the challenge of recyclable composites. Elium resin can replace thermoset-based resins for the manufacturing of laminates and composites that are fully recyclable at room temperature with comparable mechanical properties.

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Srivastava, V. K. "Dynamic Fracture Toughness Behaviour of CFRP-Foam-CFRP Sandwich Composite and Particles Filled Hybrid Glass Fiber Cloth, Graphene Nanoplates Coated Glass Fiber Strand Composite Materials under Low Impact Velocity." Journal of Materials Science Research 11, no. 1 (May 23, 2022): 70. http://dx.doi.org/10.5539/jmsr.v11n1p70.

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The main objective of the present study is to investigate the dynamic fracture toughness behaviors of CFRP-Foam-CFRP sandwich composite of V-notched through -thickness, surface, and un-notched specimens under Izod, and Charpy impact tests.  The sandwich composite structures are made of cross-plied carbon fiber reinforced plastic (CFRP) composite faces with polyurethane foam core. CFRP composites are used to combine the upper face and the lower face through the core in stitched sandwich structures. Compressive strength of weight drop impact perforated and un-perforated sandwich composite specimens are measured from a universal testing machine. Also, particles (Al2O3, CNTs, and cement) filled glass fiber cloth and graphene nanoplates coated glass fiber strands reinforced polymer hybrid composite are fabricated for V-notched, un-notched Izod impact and Charpy impact tests. The results show that weight drop impact energy is lower than the Izod impact energy but higher than the Charpy impact energy, whereas the dynamic fracture toughness of Izod impact energy is more than the Charpy and weight drop impact energy due to geometry of impactor and sandwich specimen. However energy and dynamic fracture toughness of Al2O3, CNTs, and Cement filled un-notched hybrid composites higher than the notched hybrid composites under Izod Impact. The dynamic fracture toughness and energy of CNTs filled hybrid composites is higher than the sandwich composites, Al2O3, and Cement filled hybrid composites under Charpy Impact.

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Jiang, Xueliang, Zhijie Wang, Zhen Yang, Fuqing Zhang, Feng You, and Chu Yao. "Structural Design and Sound Absorption Properties of Nitrile Butadiene Rubber-Polyurethane Foam Composites with Stratified Structure." Polymers 10, no. 9 (August 25, 2018): 946. http://dx.doi.org/10.3390/polym10090946.

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Sound absorbing composites with stratified structures, including double-layer and sandwich structures, were prepared through the combination of nitrile butadiene rubber (NBR) and polyurethane foam (PUFM). The effects of the thickness ratio of layers, different stratified structures and the variety of fillers on the sound absorption performance of the NBR-PUFM composites and the sound absorption mechanism were studied. The results show that the NBR-PUFM composite with a sandwich structure and thickness ratio of 1:8:1 displays good sound absorption, which could be improved further by adding fillers. Because the airflow resistivity, resonance absorption, interface dissipation and interface reflection were combined organically in the sandwich structure, the composites show excellent low-frequency sound absorption performance. Moreover, the composite also has advantages in cost and functionalization aspects.

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Islam, Md Rakibul, Md Arifuzzaman, Asif Karim Neon, Md Shahe Duzzaman, and Md Rafiul Islam. "Flexural Behavior of Sandwich Composite Made of JFRP Honeycomb as Core and GFRP as Skin." Journal of Engineering Advancements 01, no. 04 (November 29, 2020): 111–15. http://dx.doi.org/10.38032/jea.2020.04.001.

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The increasing demand of lightweight, strong and sustainable materials in aerospace, automobile and marine sectors is leading towards the development of new materials and structures. The sandwich composite is one of them which is well-known for their high strength to weight ratio and the fiber based sandwich structures with cellular core show comparatively good mechanical, acoustic, thermal and energy absorption properties than metallic cellular structure. The purpose of this work is to fabricate a sandwich structure with jute fiber reinforced polymer composite (JFRP) as core and glass fiber reinforced polymer composite (GFRP) as face sheet and to investigate bending properties of the fabricated structures for varying face sheet thicknesses. Skin and core honeycomb strips of the sandwich composites were manufactured using hand layup method and steel mold was used to obtain honeycomb shape. Flexural test results show that face sheet thickness has significant effect on the flexural behavior such as peak load, flexural strength and energy absorption. The failure mechanism during bending tests were also identified which would serve as a basis for future improvement of manufactured composites. The delamination at the interface between the core and the face sheet was the first catastrophic failure during bending. The presented sandwich structures are able to carry a significant amount of load even after failure.

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Nagasankar, P., S. Balasivanandha Prabu, Velmurugan Ramachandran, and R. Paskaramoorthy. "Experimental Investigation on Dynamic Characteristics of Polypropylene Honeycomb Sandwich Structures under the Influences of Different Temperatures." Applied Mechanics and Materials 606 (August 2014): 153–57. http://dx.doi.org/10.4028/www.scientific.net/amm.606.153.

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The dynamic characteristics of the Polypropylene honeycomb (PPHC) sandwich composites have been investigated under various temperatures (30°,35°,40°,45°,50°,55°,60°, 65°,70°,75° and 80°C) and different orientations (0° and 90°) of the glass fibers in the composites. Since the thermal properties of the constituent materials (glass fiber, epoxy resin and PPHC core) of the PPHC sandwich composites are different and the in-plane effect of the composites varies with the two different orientations (0° and 90°) of the fibers, the variation of the loss factor under the various temperatures are also different for these orientations. A two stage layup technique has been used to fabricate the sandwich composite specimens. Impulse technique associated with the half power bandwidth method, has been used to evaluate the natural frequency and damping values of the sandwich composite under different temperatures.

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Bělský, Petr, and Martin Kadlec. "Non-destructive Methods for Damage Assessment of Composite Sandwich Structures." MATEC Web of Conferences 188 (2018): 01008. http://dx.doi.org/10.1051/matecconf/201818801008.

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Sandwich structures are capable of absorbing large amounts of energy under impact loads which results in high structural crashworthiness. 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 ultrasonic techniques, supplemented by laser shearography. Test results have shown that water-squirt and pitch-catch techniques are the most suitable methods for the core damage evaluation. Air-coupled method showed lower sensitive for detection of some artificial defects and impact damages in honeycomb sandwiches when unfocused transducers were used. The combination of the presented methods was able to reveal most of the defects.

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OPRAN, Constantin Gheorghe, Cătălina Bivolaru, and Diana Murar. "Researches Concerning Structural and Mechanical Behavior of Sandwich Composite Polymeric Products." Key Engineering Materials 498 (January 2012): 151–60. http://dx.doi.org/10.4028/www.scientific.net/kem.498.151.

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The sandwich composite polymeric products have a wide utilization in various fileds like aircraft and automotive construction, load bearing structures, sports equipment, more specifically, wherever weight-saving is required. Sandwich composites polymeric products represent excellent examples of the potential offered by composite materials. The combination of two composite faces and a lightweight polystyrene core allows obtaining a high flexural stiffness with a weak mass. This paper deals with the analysis of the structural and mechanical behavior properties of the core, adhesive and faces, for sandwich composite polymeric products. There are also presented the investigation results on how different specific factors like: mechanical and structural behavior, interface between the faces and core, constant force resistance in time, the reinforcing elements (fiber glass), the polyester core do influence the machinability of sandwich composites polymeric products..

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Naseer, Zainab, and Zaffar Khan. "Graphene Effect on Mechanical Properties of Sandwich Panel for Aerospace Structures." Key Engineering Materials 875 (February 2021): 121–26. http://dx.doi.org/10.4028/www.scientific.net/kem.875.121.

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This research examines the mechanical properties of graphene-based polymer composites and Nomex honeycomb sandwich using a new strain sensing technique. Sandwich panels are fabricated individually with glass fibre reinforced polymers (GFRP) and face-sheets having different filler ratios of graphene nanoparticles (GNPs). These graphene nanoparticles are oxidized with (UV-O3) ozone to get graphene oxide (GO) which in turn improves resin matrix interfacial strength. Filler ratios of GO 0.0%, 0.2%, 0.6% and 1.0% by weight of poly-epoxy are fabricated for the face-sheets of composite sandwich panels. Graphene-based strain sensors are synthesized having a concentration of GNPs 5% by weight of polystyrene (PS). The strain sensors are pasted on the sandwich panels and four-point bending of the sandwich beams is performed to predict its flexural strength. The response of composite under different filler ratios of graphene oxide on mechanical properties is inspected during mechanical testing of sandwich panels and the results of (PS-GNPs) strain sensors will be compared with the strains produced during mechanical testing.

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Alsubari, S., M. Y. M. Zuhri, S. M. Sapuan, M. R. Ishak, R. A. Ilyas, and M. R. M. Asyraf. "Potential of Natural Fiber Reinforced Polymer Composites in Sandwich Structures: A Review on Its Mechanical Properties." Polymers 13, no. 3 (January 28, 2021): 423. http://dx.doi.org/10.3390/polym13030423.

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The interest in using natural fiber reinforced composites is now at its highest. Numerous studies have been conducted due to their positive benefits related to environmental issues. Even though they have limitations for some load requirements, this drawback has been countered through fiber treatment and hybridization. Sandwich structure, on the other hand, is a combination of two or more individual components with different properties, which when joined together can result in better performance. Sandwich structures have been used in a wide range of industrial material applications. They are known to be lightweight and good at absorbing energy, providing superior strength and stiffness-to-weight ratios, and offering opportunities, through design integration, to remove some components from the core element. Today, many industries use composite sandwich structures in a range of components. Through good design of the core structure, one can maximize the strength properties, with a low density. However, the application of natural fiber composites in sandwich structures is still minimal. Therefore, this paper reviewed the possibility of using a natural fiber composite in sandwich structure applications. It addressed the mechanical properties and energy-absorbing characteristics of natural fiber-based sandwich structures tested under various compression loads. The results and potential areas of improvement to fit into a wide range of engineering applications were discussed.

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Utami, Mala, Jonathan Ernest Sirait, Beny Budhi Septyanto, Aries Sudiarso, and I. Nengah Putra Apriyanto. "Laminar Composite Materials for Unmanned Aircraft Wings." Defense and Security Studies 3 (December 21, 2022): 106–12. http://dx.doi.org/10.37868/dss.v3.id211.

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Unmanned Aerial Vehicles (UAVs) have high popularity, especially in the military field, but are now also being applied to the private and public sectors. One of the UAV components that require high material technology is the wing. The latest material technology developed as a material for unmanned aircraft wings is a composite material that has high strength and lightweight. This research aims to identify composite materials that can be used for unmanned aircraft wing structures. The method used in this research is a qualitative method with a literature study approach. The results of this theoretical study show that some of the latest composite materials that have been developed into materials for unmanned aircraft wings are Laminar Composites with a sandwich structure. Laminar and sandwich composites consist of various constituent materials such as Balsa wood fiber-glass and polyester resin, microparticles, Carbon Fibre Reinforced Polymer, polymer matrix composites reinforced with continuous fibers, Polymer matrix composites, E-glass/Epoxy, Kevlar/Epoxy, Carbon/Epoxy, woven fabrics, acrylonitrile butadiene styrene-carbon (ABS) laminated with carbon fiber reinforced polymer (CFRP) and uniaxial prepreg fabrics. Laminar and sandwich composite materials are a reference for developing unmanned aircraft wing structures that have resistant strength and lightweight.

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Tian, Ce, Zhimin Tian, Xinwei Cao, and Shangwei Dong. "Lightweight design of composite sandwich corrugated structures based on variable density method." Journal of Physics: Conference Series 2808, no. 1 (July 1, 2024): 012076. http://dx.doi.org/10.1088/1742-6596/2808/1/012076.

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Abstract For the lightweight design of composite sandwich corrugated structures, a new topology optimization design scheme is proposed using the variable density method. Multi-working conditions static analysis of the composite sandwich corrugated structure is carried out by finite element software. Then, the topology optimization is carried out by using the minimum flexibility method. Finally, the results of different working conditions are coupled to propose a new composite sandwich corrugated structure. The results indicate that the structure has a weight reduction of 34% and exhibits periodicity and continuity while also meeting the necessary mechanical properties to fulfill the engineering requirements. The optimization of composite sandwich corrugated structures has been achieved, providing a new approach to the lightweight design of composite sandwich structures.

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Zhou, Hao, Rui Guo, Rongzhong Liu, and Wei Jiang. "Dynamic response of composite sandwich structures with the honeycomb-foam hybrid core subjected to underwater shock waves: Numerical simulations." Journal of Composite Materials 56, no. 6 (January 31, 2022): 911–28. http://dx.doi.org/10.1177/00219983211066386.

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The dynamic response of composite sandwich structures with honeycomb-foam hybrid cores subjected to underwater shock waves was investigated by numerical simulations. The deformation process, core compression, momentum transmitting characteristics, and energy absorbing properties of sandwich structures subjected to underwater shock waves with different initial pressures were analyzed. The dynamic responses of the composite sandwich with different core configurations were also compared. The results show that the composite sandwich structures can provide superior protection from underwater shock waves than mass equal laminate plates and the sandwich structures with hybrid cores have better performance than that with empty honeycomb cores when subjected to underwater shock waves. The research can provide reference for the lightweight design and optimization of protective structures against underwater blast loading.

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Bělský, Petr, and Martin Kadlec. "Capability of non-destructive techniques in evaluating damage to composite sandwich structures." International Journal of Structural Integrity 10, no. 3 (June 10, 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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Birman, Victor. "Thermomechanical Wrinkling in Composite Sandwich Structures." AIAA Journal 42, no. 7 (July 2004): 1474–79. http://dx.doi.org/10.2514/1.5913.

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Tarlochan, F., A. M. S. Hamouda, E. Mahdi, and B. B. Sahari. "Composite sandwich structures for crashworthiness applications." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 221, no. 2 (April 2007): 121–30. http://dx.doi.org/10.1243/14644207jmda112.

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Dear, John P., Emily Rolfe, Mark Kelly, Hari Arora, and Paul A. Hooper. "Blast Performance of Composite Sandwich Structures." Procedia Engineering 173 (2017): 471–78. http://dx.doi.org/10.1016/j.proeng.2016.12.065.

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Potluri, P., E. Kusak, and T. Y. Reddy. "Novel stitch-bonded sandwich composite structures." Composite Structures 59, no. 2 (February 2003): 251–59. http://dx.doi.org/10.1016/s0263-8223(02)00087-9.

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Katzman, Howard A., Robert M. Castaneda, and Han Sik Lee. "Moisture diffusion in composite sandwich structures." Composites Part A: Applied Science and Manufacturing 39, no. 5 (May 2008): 887–92. http://dx.doi.org/10.1016/j.compositesa.2008.01.005.

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Krot, Kamil, Edward Chlebus, and Bogumiła Kuźnicka. "Laser cutting of composite sandwich structures." Archives of Civil and Mechanical Engineering 17, no. 3 (May 2017): 545–54. http://dx.doi.org/10.1016/j.acme.2016.12.007.

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Sierakowski, R. L., and M. L. Hughes. "Force protection using composite sandwich structures." Composites Science and Technology 66, no. 14 (November 2006): 2500–2505. http://dx.doi.org/10.1016/j.compscitech.2006.03.034.

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Khoran, M., P. Ghabezi, M. Frahani, and M. K. Besharati. "Investigation of drilling composite sandwich structures." International Journal of Advanced Manufacturing Technology 76, no. 9-12 (September 30, 2014): 1927–36. http://dx.doi.org/10.1007/s00170-014-6427-x.

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Gdoutos, E. E., I. M. Daniel, and K. A. Wang. "Indentation failure in composite sandwich structures." Experimental Mechanics 42, no. 4 (December 2002): 426–31. http://dx.doi.org/10.1007/bf02412148.

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Toygar, M. Evren, Kong Fah Tee, Farshid Khosravi Maleki, and A. Cagla Balaban. "Experimental, analytical and numerical study of mechanical properties and fracture energy for composite sandwich beams." Journal of Sandwich Structures & Materials 21, no. 3 (June 19, 2017): 1167–89. http://dx.doi.org/10.1177/1099636217710003.

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In this study, the mechanical and fracture behaviour of marine sandwich-structured composite that is manufactured by vacuum-assisted resin infusion process with a PVC foam-web core, and different thicknesses of upper and lower glass fibre-reinforced polymer face sheets used as outer and inner side of the hull have been examined. The properties of PVC core, face sheet material, and composite sandwich structures are presented. Failure modes include sandwich flatwise tension, core flatwise compression, sandwich edgewise compression, and face sheet bending of manufactured composites have been investigated experimentally for marine application. The analytical solution is derived to calculate the flexural rigidity, shear stresses and maximum tensile, compression stresses in three-point bending specimens for marine sandwich composites. 3 End Notched Flexure test method has been applied to calculate the strain energy release rate. Moreover, the finite element study is carried out by using a 2D model to calculate the fracture energy (J) value numerically and virtual crack closure technique. Reasonably good results are obtained between analytical and numerical methods.

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Hong, Yi-Sheng, Xiao-Feng Lu, Xiao-Lei Zhu, Kai-Lun Zhang, and Mingji Chen. "3D printed honeycomb spacers: Tailoring sandwich structures for enhanced electromagnetic shielding." Journal of Reinforced Plastics and Composites 37, no. 16 (June 17, 2018): 1072–82. http://dx.doi.org/10.1177/0731684418782643.

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For the purpose of preventing electromagnetic emission, effective electromagnetic interference shielding materials are actively pursued. In this work, three-dimensional (3D) printing technology was employed to manipulate the honeycomb spacers, which were further assembled into multilayered graphene (GN) film-based sandwich structures. Aiming to tuning the dimensions and shapes of the conductive components in the spacers, various sizes of 3D printed honeycomb frameworks along with different conductive composites were fabricated for understanding the effects of sandwich structures and components on the electromagnetic interference shielding. By tailoring the multiple reflection of conductive interface and absorption of spacer, the as-fabricated electromagnetic interference shielding sandwich structures with a thickness of 2 mm shows considerably high shielding effectiveness (49–54.5 dB) in the X-band. With incorporating the carbon nanotube/plasticine composite into the 3D printed honeycomb structures, the tunable permittivity of the composites and designable structure of 3D printed spacer allow for substantially tuning the electromagnetic interference shielding performance in the sandwich structures. The results exhibit that both spacer thickness and the ratios of carbon nanotube-based plasticine composite to 3D printed honeycomb structures play the critical role in dominating the absorption and reflection effectiveness, suggesting novel strategy for fabricating advanced high-performance electromagnetic interference shielding structures.

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Banowati, Lies, and I. Putu Udawan Pertama. "Impact Properties of Hemp Natural – Glass Fibers Hybrid Polypropylene Sandwich Composites." Indonesian Journal of Applied Research (IJAR) 4, no. 2 (August 10, 2023): 159–69. http://dx.doi.org/10.30997/ijar.v4i2.299.

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One way to improve the mechanical properties of composite structures is by hybridizing natural and synthetic fibers. Besides that, combined with sandwich structure composites consists of two relatively strong, thin, and stiff faces separated by a core, for example, balsa, foam, and honeycomb, a relatively thick lightweight. This research develops sandwich composites for structures that have able to withstand high loads and modulus-to-weight ratios but can absorb impacts through impact tests by utilizing the raw material of jute natural fiber, which is abundant in Indonesia so that this research study can predict the effect of variations in the hybridization of hemp natural fiber and the combination of hemp natural fiber with e-glass using polypropylene core sandwich composites by using hand lay-up and vacuum bagging methods. The current impact test results show that the hemp natural-e-glass fibers hybrid sandwich composites get a higher impact strength with a value of 0,019 J/mm² than the hemp-PP honeycomb hybrid sandwich composite with a value of 0,013 J/mm². It shows that by combining e-glass fiber in the composite, it can increase its impact strength and can be a lightweight structural material as being a new alternative material of jute and e-glass natural fiber hybrid sandwich composites with polypropylene cores to substitute conventional materials such as metals which is potential for applications in the automotive, building, and unmanned aerial vehicle industries.

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Zaharia, Sebastian Marian, Mihai Alin Pop, Lucia-Antoneta Chicos, George Razvan Buican, Camil Lancea, Ionut Stelian Pascariu, and Valentin-Marian Stamate. "Compression and Bending Properties of Short Carbon Fiber Reinforced Polymers Sandwich Structures Produced via Fused Filament Fabrication Process." Polymers 14, no. 14 (July 19, 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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Kulkarni, Dr V. A. "Design and Analysis of Weight Lifting Pallet with Respect to Sandwich Pattern of Pallet." International Journal for Research in Applied Science and Engineering Technology 10, no. 1 (January 31, 2022): 1761–63. http://dx.doi.org/10.22214/ijraset.2022.40130.

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Abstract: Sandwich plates are made of face plates which are separated by core material. They are usually designed in such a way that the face plates carry the bending and in-plane loads, the face plates have relatively high stiffness and density. The core is designed to sustain shear loads; it has relatively low density and stiffness. The face plates and core can be made from various materials metals, composites, plastics, and organic materials but the core can also possess various topologies: a web, a honeycomb. A structural sandwich consists of two thin face sheets made up of stiff and powerful relatively dense Material like metal or fiber composite bonded to a thick light weight material called core. These structures are commonly used in lightweight applications such as airplanes, marine systems and wind turbine instruments. Sandwiched panels have advanced High stiffness and strength to weight ratio and during this work various sandwiched structure is applied to optimize the load of weight lifting platform. Keywords: Sandwich structures, Material Handling, Stress, Deformation, and Finite Element Analysis.

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Kadum Njim, Emad, Sadiq Emad, and Mohsin Noori Hamzah. "A RECENT REVIEW OF THE SANDWICH-STRUCTURED COMPOSITE METAMATERIALS: STATIC AND DYNAMIC ANALYSIS." Jurnal Teknologi 85, no. 5 (August 21, 2023): 133–49. http://dx.doi.org/10.11113/jurnalteknologi.v85.20282.

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Metamaterials, commonly known as synthetic composites with exotic dynamic characteristics, have recently generated increasing interest. A short description of composite metamaterial and their types, applications, and manufacturing techniques was reported. Contrary to all previous research, this investigation focuses on the recent studies of static and dynamic analysis of composite metamaterial structure and mechanical performance using experimental and finite element method analyses. Furthermore, the literature has described several methods for constructing composite sandwiches, properties, and advantages over conventional materials. Due to the wide variety of materials and configurations used in the final product, there is a corresponding diversity in manufacturing techniques. Therefore, the current research has mainly concentrated on a wealth of information that should be important to all researchers interested in keeping up with the most recent developments in composite metamaterial sandwich structures. Consequently, this study can be considered a guideline for researchers who intend further research on the mechanical behavior analysis and technology of designed composite metamaterial structures.

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Torres, J. P., R. Hoto, J. Andrés, and J. A. García-Manrique. "Manufacture of Green-Composite Sandwich Structures with Basalt Fiber and Bioepoxy Resin." Advances in Materials Science and Engineering 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/214506.

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Nowadays, there is a growing interest for the use and development of materials synthesized from renewable sources in the polymer composites manufacturing industry; this applies for both matrix and reinforcement components. In the present research, a novel basalt fibre reinforced (BFR) bioepoxy green composite is proposed as an environmentally friendly alternative to traditional petroleum-derived composites. In addition, this material system was combined with cork as core material for the fabrication of fibre composite sandwich structures. Mechanical properties of both skin and core materials were assessed through flexural and tensile tests. Finite element (FEM) simulations for the mechanical stress analysis of the sandwich material were carried out, and a maximum allowable shear stress for material failure under bending loads was established. Permeability measurements of the basalt fabrics were carried out in order to perform numerical simulations of liquid composite moulding (LCM) processes on the PAM-RTM software. The proposed green-composite sandwich material was used for the fabrication of a longboard as a case study for a sports equipment application. Numerical simulations of the mould filling stage allowed the determination of an optimal mould filling strategy. Finally, the load-bearing capacity of the board was studied by means of FEM simulations, and the presented design proved to be acceptable for service.

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Buican, George Razvan, Sebastian-Marian Zaharia, Mihai Alin Pop, Lucia-Antoneta Chicos, Camil Lancea, Valentin-Marian Stamate, and Ionut Stelian Pascariu. "Fabrication and Characterization of Fiber-Reinforced Composite Sandwich Structures Obtained by Fused Filament Fabrication Process." Coatings 11, no. 5 (May 19, 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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Chang, Bianhong, Zhenning Wang, and Guangjian Bi. "Study on the Energy Absorption Characteristics of Different Composite Honeycomb Sandwich Structures under Impact Energy." Applied Sciences 14, no. 7 (March 27, 2024): 2832. http://dx.doi.org/10.3390/app14072832.

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A honeycomb structure is a sandwich structure widely used in fuselage, among which the hexagonal honeycomb core is the most widely used. The energy absorption characteristics and impedance ability of the structure are the main reasons that directly affect the energy absorption characteristics of the honeycomb sandwich structure. Therefore, it is necessary to study the out-of-plane mechanical properties of the composite honeycomb sandwich structure. Based on the numerical simulation results, the energy absorption characteristics of several composite honeycomb sandwich structures are verified by drop hammer impact experiments. The research shows that the transient energy absorption characteristics of the composite honeycomb sandwich structure are mainly related to the cell size of the honeycomb structure. The smaller the size of the front cell, the stronger the overall impact resistance; the strength of the composite honeycomb sandwich structure exceeds that of 7075 aluminum alloy-NOMEX and carbon fiber-NOMEX honeycomb sandwich structures. In this paper, the energy absorption characteristics of composite honeycomb sandwich structures under different impact energy are compared and studied. The displacement, force and energy curves of energy absorption characteristics related to time variables are analyzed. The difference in protective performance between the composite honeycomb sandwich structure and existing airframe structure is compared and studied. The optimal structural design parameters of composite honeycomb sandwich under low-speed impact of drop hammer are obtained. The maximum energy absorption per unit volume of the designed honeycomb sandwich structure is 171.7% and 229.8% higher than that of the NOMEX-AL and NOMEX-C structures. The 6.4 mm and 3 mm cell sizes show good characteristics in high-speed buffering and crashworthiness. The composite honeycomb sandwich airframe structure can improve the anti-damage performance of the UAV airframe structure, ensure the same thickness and lightweight conditions as the existing honeycomb sandwich airframe structure, and improve the single-core bearing mode of the existing airframe structure.

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Gu, Xuetao, Jiawen Li, Ji Huang, Yaoliang Ao, and Bingxiong Zhao. "Numerical Analysis of the Impact Resistance of Composite A-Shaped Sandwich Structures." Materials 16, no. 14 (July 16, 2023): 5031. http://dx.doi.org/10.3390/ma16145031.

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This paper focuses on the finite element analysis simulation of the impact properties of composite sandwich structures made of carbon fiber-reinforced polymer lamina. In the existing studies, the composite sandwich structures with A-shaped cores have superior mechanical properties under quasi-static plane compression loads compared to W-shaped, Y-shaped, and X-shaped cores. However, there is limited research on the impact resistance of this structure. This paper studied the resistance of a composite A-shaped core structure to ballistic impact. Using ABAQUS/explicit finite element analysis software, ballistic impact tests for the composite A-shaped core structure were simulated based on the Hashin and Yeh failure criteria with a progressive damage model introduced in the user-defined subroutine VUMAT. First, the composite Y-shaped core sandwich structure was verified via experiments and simulations to determine the accuracy of the method, and then the composite A-shaped sandwich structure was subjected to a series of ballistic impact simulations. With varied impact velocity, the damage to the front and rear face sheet and cores via ballistic loads was simulated to illustrate the overall dynamic response process of the sandwich structure. Subsequently, a curve was fitted using a ballistic limit velocity equation, which was used as the criterion to evaluate the impact resistance of the composite A-shaped core structure. The results showed that, under the same relative density and the same number of component layers, the ballistic limit velocity of the composite A-shaped core sandwich structure was bigger than the composite Y-shaped core sandwich structure. The composite A-shaped core structure had 12.23% higher ballistic limit velocity than the composite Y-shaped core, indicating the impact resistance capabilities of the A-shaped core structure. In addition, the impact location’s effect on the impact response was investigated.

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RUSU, Bogdan, Simona BLINDU BLINDU, Andra MICU, and Valentin SOARE. "Guidelines for Aircraft Composite Panels." INCAS BULLETIN 12, no. 1 (March 1, 2020): 217–28. http://dx.doi.org/10.13111/2066-8201.2020.12.1.21.

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The objective of this paper is to give a general perspective and present some elementary steps for manufacturing aircraft sandwich panel composites. Composite materials have been widely used in high performance sectors of the aerospace and automotive industry, and there is considerable knowledge and confidence in their static, dynamic and crashworthiness properties. Sandwich composites are becoming more and more used in airframe structural design, mainly for their ability to substantially reduce weight while maintaining their high mechanical properties. The steps for manufacturing a sandwich composite that meets all the requirements for exploitation are very precise and rigorous, involving specific design requirements, specific materials selection and specific manufacturing conditions starting with the lay-up procedure and up to the curing process inside an autoclave. After the curing process, destructive and nondestructive tests and experiments are performed on the composite structures in order to validate the products. At the same time, this paper presents a short briefing about the implication of 3D printing technologies with high temperature resistance resins for sandwich cores used in aerospace applications.

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Yartsev, Boris, Viktor Ryabov, and Lyudmila Parshina. "Dissipative properties of composite structures. 1. Statement of problem." Transactions of the Krylov State Research Centre 4, no. 398 (November 15, 2021): 24–34. http://dx.doi.org/10.24937/2542-2324-2021-4-398-24-34.

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Object and purpose of research. The object under study is a sandwich plate with two rigid anisotropic layers and a filler of soft isotropic viscoelastic polymer. Each rigid layer is an anisotropic structure formed by a finite number of orthotropic viscoelastic composite plies of arbitrary orientation. The purpose is to develop a mathematical model of sandwich plate. Materials and methods. The mathematical model of sandwich plate decaying oscillations is based on Hamilton variational principle, Bolotin’s theory of multilayer structures, improved theory of the first order plates (Reissner-Mindlin theory), complex modulus model and principle of elastic-viscoelastic correspondence in the linear theory of viscoelasticity. In description of physical relations for rigid layers the effects of oscillation frequencies and ambient temperature are considered as negligible, while for the soft viscoelastic polymer layer the temperaturefrequency relation of elastic-dissipative characteristics are taken into account based on experimentally obtained generalized curves. Main results. Minimization of the Hamilton functional makes it possible to reduce the problem of decaying oscillations of anisotropic sandwich plate to the algebraic problem of complex eigenvalues. As a specific case of the general problem, the equations of decaying longitudinal and transversal oscillations are obtained for the globally orthotropic sandwich rod by neglecting deformations of middle surfaces of rigid layers in one of the sandwich plate rigid layer axes directions. Conclusions. The paper will be followed by description of a numerical method used to solve the problem of decaying oscillations of anisotropic sandwich plate, estimations of its convergence and reliability are given, as well as the results of numerical experiments are presented.

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Wang, Yongwei, Deng Zhou, Gang Yan, and Zhuangjie Wang. "Experimental and Numerical Study on Residual Strength of Honeycomb Sandwich Composite Structure after Lightning Strike." Aerospace 9, no. 3 (March 14, 2022): 158. http://dx.doi.org/10.3390/aerospace9030158.

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Honeycomb sandwich composite structures are widely used in various aircraft structures due to their unique performance. However, honeycomb sandwich composite structures are prone to lightning damage that threatens the structure safety. Therefore, it is necessary to assess the residual mechanical properties of honeycomb sandwich composite structures after a lightning strike. In this study, simulated lightning strike tests were first conducted for honeycomb sandwich panels with and without carbon nanotube film (CNTF) to obtain different damage scenarios and study the protection effect of CNTF. Then, the residual compressive strength of the panels with lightning strike damage was predicted using a progressive damage analysis method and verified with the experimental results. It was found that the numerical prediction results agree with the experimental results. The size and extent of lightning damage have an important effect on the compression damage mode of honeycomb sandwich panel with closed edges.

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Halim, Zahurin, Zuraida Ahmad, and Syarifah Nur Adilla Syed Taha. "Effect of Fibre Surface Treatment on the Properties of Eco-Core Sandwich Structures." Advanced Materials Research 1115 (July 2015): 321–24. http://dx.doi.org/10.4028/www.scientific.net/amr.1115.321.

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The growing ecological, social and economic awareness, high rate of depletion of petroleum resources, concepts of sustainability and new environmental regulations have stimulated the search for green materials compatible with the environment. The focus of this research is to study the effect of fibre surface treatment as far as kenaf fibre composite sandwich structure is concern. The kenaf fibre is subjected to alkali treatment. Upon completion, the treated kenaf fibre is used for fabrication of composite sandwich structure by utilizing thermoset resin which is epoxy as the matrix and galvanized steel as the face skin. The sandwich structure undergone SEM for morphological study and three point bending test to identify the bending properties. Treated kenaf fibres shows improvement after the alkali treatment compared to untreated kenaf fibre in the composite sandwich structure.Keywords: Composite sandwich structures; biodegradable; kenaf fibres ; surface treatment; morphology

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Jiang, Qihong, Guiyong Chen, Abhideep Kumar, Andrew Mills, Krutarth Jani, Vasudevan Rajamohan, Barathan Venugopal, and Sameer Rahatekar. "Sustainable Sandwich Composites Manufactured from Recycled Carbon Fibers, Flax Fibers/PP Skins, and Recycled PET Core." Journal of Composites Science 5, no. 1 (December 23, 2020): 2. http://dx.doi.org/10.3390/jcs5010002.

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European union end of life vehicle directive mandates the use of more sustainable/recyclable materials in automotive industries. Thermoplastics matrix-based composites allow recyclability of composites at the end of life; however, their processing technology is more challenging than thermoset composites. Manufacturing process and mechanical testing of sustainable sandwich composite made from sustainable materials: flax, recycled carbon fiber, polypropylene, and recycled PET foam are presented in this article. High pressure compression molding with adhesive thermoplastic polymer film was used for manufacturing sandwich composite skin. The recycled PET foam core was integrated/joined with the skin using a thermoplastics adhesive film. A three-point bending test was conducted to compare the flexural properties. The results show that such sustainable sandwich composites will be an excellent material for truck side panel to operate in adverse wind/storm conditions. The sustainable sandwich composite can potentially be an excellent candidate for the fabrication of light-duty, lightweight, and low-cost engineering structures in automotive industry to meet the EU end of life requirements.

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Journal articles on the topic 'Composite Sandwich Structures'

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