Littérature scientifique sur le sujet « Composite wrapping »
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Articles de revues sur le sujet "Composite wrapping"
1
O RUAN, FANGTAO, CHENGLONG XIA, LI YANG, ZHENZHEN XU et FEIYAN TAO. « Effect of filaments diameter on the mechanical properties of wrap hybrid CFRP ». Industria Textila 72, no 02 (22 avril 2021) : 144–48. http://dx.doi.org/10.35530/it.072.02.1733.
Texte intégralRésumé :
In this paper, the vine-like structure of carbon bundles was designed through polyester fibre wrapping for better mechanical properties. The effect of wrapped hybrid structure and diameters of polyester fibre on the mechanical properties of carbon-polyester fibre/epoxy unidirectional composites was investigated experimentally. Five kinds of specimens with different polyester filament diameters were produced. The impact, tensile and unidirectional compressive properties of WHC (Wrap Hybrid Composite) were measured. Experimental results show that: it can be developed with strength and toughness properties far superior to those of their constituents, the compressive fracture morphology of specimens indicated that the fracture patterns of composites depend on wrapped hybrid structure, polyester fibres with higher tensile strengths provide better impact resistance, while thinner wrapping fibres enhance the compression properties of the composite material more effectively. The diameter of the wrapping fibre should be optimized as per the application of the composite material. The vine-like structure can provide a new design method for the structural design of continue fibre reinforced composite materials.
2
Shaktivell M.Letchumanan, Ahmad Mubarak Tajul Arifin, Nor Adrian Nor Salim et Ishkrizat Taib. « A Comparative Analysis on the Optimization of Carbon Fibre Reinforced Polymer and Glass Fiber Reinforced Polymers as Wrapping Structures on Defected Piping System using Computational Simulation Approach ». Journal of Advanced Research in Applied Mechanics 118, no 1 (2 juin 2024) : 79–89. http://dx.doi.org/10.37934/aram.118.1.7989.
Texte intégralRésumé :
This study examined the application of carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) as wrapping structures for defective pipe systems. The structural behavior and performance of the CFRP and GFRP wrapping structures were assessed using computational simulation methodologies. The goal of the study was to determine the best wrapping material for strengthening the integrity and reliability of piping systems with defects by comparing the results of the simulations. The study evaluated the capability of the proposed composite wrapping structure through CAD simulation. The simulations provided preliminary analysis and visually depicted deformations, aiding in the selection of an optimized lamination orientation for the composite wrapping structure in real-world applications. Eventually, this approach could have alleviated two primary failure modes that were common in composite repair: composite overloading due to excessive thickness and composite delamination from the substrate. The results of this study would have helped enhance effective and efficient pipe repair techniques in a variety of industries by offering useful insights into the selection and use of suitable wrapping structures for repairing defective pipes.
3
Archana, D. P., H. N. Jagannatha Reddy, N. Jeevan, R. Prabhakara, M. U. Aswath et Basavaraju Paruti. « Natural Jute Fibre-Reinforced Polymer Composite System for Posttensioned Beam Strengthening in Flexure ». Advances in Materials Science and Engineering 2021 (27 novembre 2021) : 1–14. http://dx.doi.org/10.1155/2021/2905150.
Texte intégralRésumé :
Existing structures require repair and strengthening owing to degradation caused by incorrect design and construction, environmental impacts, or structural upgradation to meet new seismic design standards or to correct execution problems that occurred during construction. These strengthening requirements can be satisfied by a variety of strengthening techniques. The creation of a fibre-reinforced polymer (FRP) composite system offers a new design method for the strengthening of existing structures. In this study, posttensioned beams are strengthened by using sustainable materials such as natural jute fibre-reinforced polymer (FRP) composites. The performance of these composite systems in the flexural strengthening of posttensioned beams was used to assess their effectiveness. Consequential result for longitudinal reinforcement throughout the length of the beam for flexural strengthening was evaluated. Flexural performance, crack width, ductility, and load-deflection relationship study of control beams (Scheme A) and retrofitted beams (Schemes B and C) under different wrappings were considered in the investigation. An experimental study depicts that using the full wrapping (FW) technique increases the flexural strength of PSC beams wrapped in JFRP by 23% and, by using the strip wrapping (SW) technique, the flexural strength is increased by 10%. The JFRP composite system of strengthening has shown the highest deformability index and showed that the JFRP material has enormous potential as a structural strengthening material.
4
Tarnai, T., F. Kovács, P. W. Fowler et S. D. Guest. « Wrapping the cube and other polyhedra ». Proceedings of the Royal Society A : Mathematical, Physical and Engineering Sciences 468, no 2145 (18 avril 2012) : 2652–66. http://dx.doi.org/10.1098/rspa.2012.0116.
Texte intégralRésumé :
An infinite series of twofold, two-way weavings of the cube, corresponding to ‘wrappings’, or double covers of the cube, is described with the aid of the two-parameter Goldberg–Coxeter construction. The strands of all such wrappings correspond to the central circuits (CCs) of octahedrites (four-regular polyhedral graphs with square and triangular faces), which for the cube necessarily have octahedral symmetry. Removing the symmetry constraint leads to wrappings of other eight-vertex convex polyhedra. Moreover, wrappings of convex polyhedra with fewer vertices can be generated by generalizing from octahedrites to i -hedrites, which additionally include digonal faces. When the strands of a wrapping correspond to the CCs of a four-regular graph that includes faces of size greater than 4, non-convex ‘crinkled’ wrappings are generated. The various generalizations have implications for activities as diverse as the construction of woven-closed baskets and the manufacture of advanced composite components of complex geometry.
5
Ruan, Fangtao, Zhenzhen Xu, Dayin Hou, Yang Li et Changliu Chu. « Enhancing Longitudinal Compressive Properties of Unidirectional FRP Based on Microbuckling Compression Failure Mechanism ». Journal of Engineered Fibers and Fabrics 13, no 1 (mars 2018) : 155892501801300. http://dx.doi.org/10.1177/155892501801300110.
Texte intégralRésumé :
In this study, a new methodology to improve the longitudinal compressive strength and modulus of ultra-high molecular weight polyethylene (UHMWPE) fiber-reinforced epoxy resin matrix is developed. The proposed method involves wrapping a UHMWPE fiber bundle with a poly-p-phenylene benzobisoxazole fiber filament using a winding method, and using these bundles to fabricate unidirectional UHMWPE fabric. UHMWPE/epoxy composites were fabricated using vacuum-assisted resin-transfer molding (VARTM), and the compression properties of the composite were evaluated and compared to investigate the effect of the filament wrapping. Improvements in the compressive modulus were achieved for filaments wound with applied tension, and when increasing the filament-winding spacing; however, the compressive strength decreased with an increase in the filament-winding spacing. Results obtained confirm that fiber microbuckling failure occurred in the composite under longitudinal compression, and that inhibiting the buckling length of the fiber improved compressive properties. These results may be useful when designing the mechanical properties of fiber-reinforced polymer composites.
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Kasimzade, A., et S. Tuhta. « Analytical, Numerical and Experimental Examination of Reinforced Composites Beams Covered with Carbon Fiber Reinforced Plastic ». Journal of Theoretical and Applied Mechanics 42, no 1 (1 mars 2012) : 55–70. http://dx.doi.org/10.2478/v10254-012-0004-1.
Texte intégralRésumé :
Analytical, Numerical and Experimental Examination of Reinforced Composites Beams Covered with Carbon Fiber Reinforced PlasticIn the article, analytical, numerical (Finite Element Method) and experimental investigation results of beam that was strengthened with fiber reinforced plastic-FRP composite has been given as comparative, the effect of FRP wrapping number to the maximum load and moment capacity has been evaluated depending on this results. Carbon FRP qualitative dependences have been occurred between wrapping number and beam load and moment capacity for repair-strengthen the reinforced concrete beams with carbon fiber. Shown possibilities of application traditional known analysis programs, for the analysis of Carbon Fiber Reinforced Plastic (CFRP) strengthened structures.
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Pan, Shengshan, Muzhou Zhao, Bassem Andrawes, Hang Zhao et Lian Li. « Compressive behavior of cylindrical rubber buffer confined with fiber reinforced polymer ». Journal of Low Frequency Noise, Vibration and Active Control 39, no 3 (17 juillet 2018) : 470–84. http://dx.doi.org/10.1177/1461348418783570.
Texte intégralRésumé :
This paper presents a new composite buffer for mitigating the lateral displacement of structures under seismic loading. The buffer consists of a cylindrical rubber wrapped with fiber reinforced polymer composite. The uniaxial compressive stiffness of the buffer can be controlled by varying either the number of fiber reinforced polymer layers or the wrapping scheme of fiber reinforced polymer. First, a test program is carried out to investigate the impact of various parameters on the compressive stiffness and strength of the new buffer including thickness of fiber reinforced polymer, wrapping scheme, and method of wrapping of fiber reinforced polymer. Next, a theoretical formulation is derived to describe the constitutive behavior of fiber reinforced polymer wrapped rubber under uniaxial compression using strain energy density function of the Yeoh N-order polynomial model. Finally, a finite element model is developed to analyze the new composite buffer and the numerical results are validated using the experimental results. The results of the study show that the Yeoh model is able to simulate the behavior of rubber under compression. The new composite buffer exhibits significantly higher stiffness and strength than that of pure rubber. Wrapping scheme plays an important role in defining the mechanical behavior of the buffer. The study also shows good agreement between the numerical simulation and the experimental results.
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Lin, Jia Horng, Zhi Cai Yu, Jian Fei Zhang et Ching Wen Lou. « Manufacturing Techniques and Functional Properties of the Bamboo Charcoal/Antibacterial/Stainless Steel Metal Composite Woven Fabric ». Advanced Materials Research 910 (mars 2014) : 238–41. http://dx.doi.org/10.4028/www.scientific.net/amr.910.238.
Texte intégralRésumé :
In this research, the B/A/S composite yarns were fabricated using the stainless steel wires as core yarn, antibacterial nylon and bamboo charcoal polyester filaments as inner wrapped yarn and outer wrapped yarn, respectively. The composite yarns with a wrapping number of 8, 11, 14 turns/cm were fabricated on a hollow spindle spinning machine. Furthermore, the composite fabrics were woven with the B/A/S composite yarns as weft yarns and the PET as the warp yarns. These fabrics were evaluated in terms of far infrared (FIR) emissivity and the air permeability. The presence of the bamboo charcoal was found to increase the FIR emissivity. The highest of the FIR emissivity was obtained when the weft yarns with a wrapping number of 11 turns/cm. The lamination numbers of the woven fabrics varied from 1-5 layers. The far infrared emissivity and air permeability of the woven fabrics was 0.94 and 268 cm3/cm2/s when the lamination numbers was 2 layers and the wrapping number was 11 turns/cm.
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Bohse, Juergen, Georg W. Mair et Pavel Novak. « Acoustic Emission Testing of High-Pressure Composite Cylinders ». Advanced Materials Research 13-14 (février 2006) : 267–72. http://dx.doi.org/10.4028/www.scientific.net/amr.13-14.267.
Texte intégralRésumé :
AE studies were performed considering pressure cylinders of design1 Type II – metallic liner with hoop composite wrapping, Type III – metallic load sharing liner with full composite wrapping and Type IV – all-composite cylinder. The AE technique has to be improved so far that for different design types of cylinders standard AE equipment can be used in an easy and practicable way under normal conditions of production and service. The paper presents our 8 years of experience in this application area using conventional AE measuring technique. Potentials, requirements and limits for detection of manufacturing faults and in-service damages of highpressure composite cylinders are discussed. 1Cylinder types classification in accordance with ECE R 110 / ISO 11439
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Wang, Kaifeng, Mengjie Liu, Jie Cao, Jiayong Niu et Yunxia Zhuang. « Bearing Characteristics of Composite Foundation Reinforced by Geosynthetic-Encased Stone Column : Field Tests and Numerical Analyses ». Sustainability 15, no 7 (29 mars 2023) : 5965. http://dx.doi.org/10.3390/su15075965.
Texte intégralRésumé :
In order to study the bearing characteristic of the geosynthetic-encased stone column (GESC) on the composite foundation, a series of field tests and numerical simulation were carried out on the composite foundations reinforced by the traditional stone column and the GESC. The pile–soil stress ratio, excess pore water pressure and lateral displacement of two kinds of composite foundations were monitored. The effects of geotextile stiffness, geotextile wrapping length and gravel internal friction angle on the composite foundation with the GESC were analyzed by establishing different numerical models. The results show that the GESC can bear larger loading compared with the traditional stone column. The pile–soil stress ratio of the composite foundation with the traditional stone column gradually increases from 1.1 to 1.5 with the increasing of the embankment height. However, the pile–soil stress ratio of the composite foundation with the GESC reaches 1.5 at the initial filling stage and increases to 1.7 with the filling construction. The drainage effect of the GESC is better than that of the traditional stone column, and the GESC can effectively improve the overall stiffness of stone column, so as to reduce the lateral displacement of soil mass. The increases of geotextile stiffness, geotextile wrapping length and gravel internal friction angle can improve the bearing performance of the composite foundation with the GESC. However, after geotextile stiffness and wrapping length reach a certain value, the influence of its lifting amount on the composite foundation will be reduced.
Thèses sur le sujet "Composite wrapping"
1
Selver, Erdem. « Tow level hybridisation for damage tolerant composites ». Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/tow-level-hybridisation-for-damage-tolerant-composites(8cf53f8c-165f-4e8b-b67f-f8fd34c327e2).html.
Texte intégralRésumé :
Fibre reinforced composites have higher specific strength and stiffness in comparison to metals. However, composites are susceptible to impact damage resulting in degradation of mechanical properties especially compression strength. Numerous studies have been conducted to improve the impact damage tolerance of composite laminates using modified resin systems, thermoplastic matrices, 3-D fibre architectures and through thickness reinforcement. This work is primarily focussed on incorporating non dissolvable polypropylene fibres (PP) in a thermoset matrix for improving the damage tolerance. Commingling and wrapping techniques have been investigated. PP fibres have been incorporated at the preform stage and hence do not adversely affect the viscosity of the resin during infusion. The healing effect of PP fibres on impact damaged composite laminates when heating is introduced has also been studied. High velocity impact test results showed that using commingled glass/PP fibres increased the total energy absorption of composite laminates by 20% due to the extensive plastic deformation of the PP fibres and through the use of toughening mechanisms in the form of resin cracking and delamination. It has been found that PP fibres provide protection to the glass fibres during low velocity impact loading, so fewer fibre breakages occur which lead to improved residual properties compared with pristine glass laminates. Compression after impact (CAI) tests showed that the residual strength as a percentage of non-impacted strength increased with percentage of PP fibres used. For impact of 20-50J, glass/epoxy laminates retained 32 45% of their compressive strength while laminates with 7%, 13% and 18% PP fibres retained 37 50%, 42-52% and 43-60% of their compressive strength, respectively. It was also observed that glass/PP woven laminates had better compressive strength retention (62 83%) than the glass/PP non-crimp laminates (37-50%). Composite laminates with high-modulus PP fibres (Innegra) exhibited higher residual compression strengths in comparison to laminates with lower modulus PP fibres. For 15-50J impact, glass/Innegra laminates showed residual compression strength of 50 63% in comparison to 39-60%; laminates without thermoplastic fibres exhibited 33 43% residual compression strength. Modulus of thermoplastic fibres appears to be important at higher energy levels. Healing of damaged commingled laminates produced a significant reduction in the damage area and a corresponding increase in CAI strength after heating at 200ºC; CAI strength of healed laminates is about 85% of undamaged samples in comparison to 60% for non-healed samples. A novel micro-wrapping technique, developed in this work, demonstrated significant reduction in damage area (46%) in comparison to the commingling method. Core wrapped laminates had higher residual strength (43-60%) than glass laminates (33-43%). Better PP distribution in core-wrapped composites helped to decrease the PP rich areas and the impact damage did not propagate easily in comparison to commingled composites. However due to the reduction in damage area, impact energy absorption in core wrapped laminates was lower than for commingled.
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Promis, Geoffrey. « Composites fibres / matrice minérale : du matériau a la structure ». Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00646976.
Texte intégralRésumé :
Ce travail de recherche est axé sur le développement de composites à liant phosphatique et fibres de renfort en verre E pour diverses applications structurales en Génie Civil. Dans une première partie, un bilan bibliographique nous permet d'identifier les principaux facteurs aux différentes échelles (nano, micro, méso et macro) ayant une influence sur le comportement global de composites à matrice minérale. Dans un second temps, les propriétés mécaniques et physico-chimiques des constituants sont présentées. Nous développons une méthodologie spécifique de caractérisation en traction, en compression et en cisaillement. Le développement de procédures expérimentales particulières en compression et en cisaillement permet l'identification des lois de comportement et l'évaluation des seuils d'endommagement et charges de rupture. La prévision des différents termes de rigidité élastique des systèmes composites est évaluée à partir d'expressions reprenant les principes de base de la micromécanique des composites. L'analyse du comportement à rupture est abordée au plan mésoscopique en considérant deux critères de résistance en plasticité, anisotropie (Tsai-Wu) et en contrainte normale, de cisaillement (Mohr-Coulomb). La deuxième partie de la recherche est consacrée à l'étude d'éléments structuraux mettant en oeuvre les formulations pultrudés de ces systèmes composites. L'expérimentation de poutres, présentant un rapport de la hauteur de la section à la portée de la poutre compris entre 1/15 et 1/50, met en évidence des modes de rupture spécifiques confirmant les faibles caractéristiques du matériau vis-à-vis de l'effort tranchant, du cisaillement interlaminaire et de la décohésion fibre/matrice. L'optimisation de la conception et du dimensionnement des poutres se poursuit en considérant des modifications d'ordre technologique : modification des sections par addition d'entretoises, confinement des sections par tressage circonférentiel, application d'un confinement par stratification directe. Pour chaque type de structures, nous cherchons à définir les limites de validité des méthodes de dimensionnement usuelles en examinant plus particulièrement la conformité des hypothèses de calcul (Navier-Bernoulli, Saint Venant), la cohérence des équations d'équilibre au regard de la cinématique dans chaque section. Dans un second temps, nous considérons des développements intégrant les non linéarités de comportement ou des modèles d'équilibre de type force adaptés à la redistribution interne des efforts tranchants.
3
Pramanik, Debabrata. « Polymer Assisted Dispersion of Carbon Nanotubes (CNTs) and Structure, Electronic Properties of CNT - Polymer Composite ». Thesis, 2017. http://etd.iisc.ac.in/handle/2005/3563.
Texte intégralRésumé :
Carbon nanotubes possess various unique and interesting properties. They have very high thermal and electrical conductivities, high stiffness, mechanical strength, and optical properties. Due to these properties, CNTs are widely used materials in a variety of fields. It is used for biotechnological and biomedical applications, as chemical and biosensor, in energy storage and field emission transistor. Experimentally synthesized CNTs are generally found in bundle form due to the strong vander Waals (vdW) at-traction between the individual tubes. To use CNTs in real life applications, we often require specific nanotubes with particular characteristics. The nanotube bundle is a mixture of various chirality, diameters and electronic properties (metallic and semiconducting). Only thermal energy is not sufficient to disperse nanotubes from the bundle geometry overcoming the strong vdW attraction between nanotubes. The hydrophobic and insoluble nature of CNTs in the aqueous medium makes the dispersion of CNTs even more difficult. So, it is a big challenge to get single pristine nanotube from the bundle geometry.
Many experimental and theoretical studies have addressed the problem of nanotube dispersion from the bundle geometry. Ultrasonic dispersing method is a widely used technique for this purpose where ultrasonic sound is applied to agitate particles in a system. Other methods include using different organic and inorganic solutions, various surfactant molecules, different polymers as dispersing agents. In this study we extend our e orts to develop some better methods and improved dispersing agents. In this thesis, we address the problem of CNT dispersion. To address this issue, we rst give a quantitative estimation of the effective interaction between nanotubes. Next, we introduce different polymers (ssDNA and dendrimers) as external agents and show that they help to overcome the strong adhesive interaction between CNTs and make nanotube dispersion possible from the bundle geometry. For all of the works presented in this thesis, we have used fully atomistic MD simulation and DFT level calculations. We study ssDNA-CNT complex using all-atom MD simulation and calculate various structural quantities to show the stability of ssDNA-CNT complex in aqueous medium. The adsorption of ssDNA bases on CNT surface is driven by - interaction between nucleic bases and CNT. Using the potential of mean forces (PMF) calculation, we study the binding strength of the polynucleotide ssDNA for poly A, T, G, and C with CNT of chirality (6,5). From the PMF calculation, we show the binding sequence to be A > T > C > G. Except for poly G, our result is in good agreement with earlier reported single molecule force spectroscopy results where the sequence of binding interaction was reported to be A > G > T > C. To explore how the interaction between two CNTs mod-i ed in presence of ssDNA between them, we perform PMF calculation between the two ssDNA-wrapped CNTs. The PMF shows the sequence of interaction strength between two ssDNA-wrapped CNTs for different nucleic bases to be T > A > C > G. Thus, from PMF calculations we show the poly T to have the highest dispersion efficiency, which is consistent with earlier reported experimental study. Our PMF calculation shows that poly C and poly G reduce the attraction between two CNTs drastically, whereas poly A and poly T make the interaction fully repulsive in nature. We also present microscopic pictures of the various binding conformations for ssDNA adsorbed on CNT surface.
We also study the dendrimer-CNT complex for both the PAMAM and PETIM dendrimers of different generations at various protonation states and present microscopic pictures of the complex. We calculate PMF between two dendrimer wrapped CNTs and show that protonated and higher generations (G3, G4, and so forth) non-protonated PAMAM dendrimers can be used as e ective agents to disperse CNTs from bundle geometry. We also study the chirality dependence of PMF respectively.
Finally, we study the interaction of mannose dendrimer with CNTs and show that the wrapping of mannose dendrimer can drive a metal to semiconducting transition in a metallic CNT. We attribute the carbon-carbon bond length assymetry in CNT due to the wrapping of mannose dendrimer as the reason for this band gap opening which leads to metal-semiconductor transition in CNT. Thus, the wrapping of mannose dendrimer on CNT can change its electronic properties and can be used in the band gap engineering of CNT in future nanotechnology.
Thus, the works carried out here in this dissertation will help to address the problem of nanotube dispersion from the bundle geometry which will in turn help to use CNT for various applications in diverse fields.
4
Pramanik, Debabrata. « Polymer Assisted Dispersion of Carbon Nanotubes (CNTs) and Structure, Electronic Properties of CNT - Polymer Composite ». Thesis, 2017. http://etd.iisc.ernet.in/2005/3563.
Texte intégralRésumé :
Carbon nanotubes possess various unique and interesting properties. They have very high thermal and electrical conductivities, high stiffness, mechanical strength, and optical properties. Due to these properties, CNTs are widely used materials in a variety of fields. It is used for biotechnological and biomedical applications, as chemical and biosensor, in energy storage and field emission transistor. Experimentally synthesized CNTs are generally found in bundle form due to the strong vander Waals (vdW) at-traction between the individual tubes. To use CNTs in real life applications, we often require specific nanotubes with particular characteristics. The nanotube bundle is a mixture of various chirality, diameters and electronic properties (metallic and semiconducting). Only thermal energy is not sufficient to disperse nanotubes from the bundle geometry overcoming the strong vdW attraction between nanotubes. The hydrophobic and insoluble nature of CNTs in the aqueous medium makes the dispersion of CNTs even more difficult. So, it is a big challenge to get single pristine nanotube from the bundle geometry.
Many experimental and theoretical studies have addressed the problem of nanotube dispersion from the bundle geometry. Ultrasonic dispersing method is a widely used technique for this purpose where ultrasonic sound is applied to agitate particles in a system. Other methods include using different organic and inorganic solutions, various surfactant molecules, different polymers as dispersing agents. In this study we extend our e orts to develop some better methods and improved dispersing agents. In this thesis, we address the problem of CNT dispersion. To address this issue, we rst give a quantitative estimation of the effective interaction between nanotubes. Next, we introduce different polymers (ssDNA and dendrimers) as external agents and show that they help to overcome the strong adhesive interaction between CNTs and make nanotube dispersion possible from the bundle geometry. For all of the works presented in this thesis, we have used fully atomistic MD simulation and DFT level calculations. We study ssDNA-CNT complex using all-atom MD simulation and calculate various structural quantities to show the stability of ssDNA-CNT complex in aqueous medium. The adsorption of ssDNA bases on CNT surface is driven by - interaction between nucleic bases and CNT. Using the potential of mean forces (PMF) calculation, we study the binding strength of the polynucleotide ssDNA for poly A, T, G, and C with CNT of chirality (6,5). From the PMF calculation, we show the binding sequence to be A > T > C > G. Except for poly G, our result is in good agreement with earlier reported single molecule force spectroscopy results where the sequence of binding interaction was reported to be A > G > T > C. To explore how the interaction between two CNTs mod-i ed in presence of ssDNA between them, we perform PMF calculation between the two ssDNA-wrapped CNTs. The PMF shows the sequence of interaction strength between two ssDNA-wrapped CNTs for different nucleic bases to be T > A > C > G. Thus, from PMF calculations we show the poly T to have the highest dispersion efficiency, which is consistent with earlier reported experimental study. Our PMF calculation shows that poly C and poly G reduce the attraction between two CNTs drastically, whereas poly A and poly T make the interaction fully repulsive in nature. We also present microscopic pictures of the various binding conformations for ssDNA adsorbed on CNT surface.
We also study the dendrimer-CNT complex for both the PAMAM and PETIM dendrimers of different generations at various protonation states and present microscopic pictures of the complex. We calculate PMF between two dendrimer wrapped CNTs and show that protonated and higher generations (G3, G4, and so forth) non-protonated PAMAM dendrimers can be used as e ective agents to disperse CNTs from bundle geometry. We also study the chirality dependence of PMF respectively.
Finally, we study the interaction of mannose dendrimer with CNTs and show that the wrapping of mannose dendrimer can drive a metal to semiconducting transition in a metallic CNT. We attribute the carbon-carbon bond length assymetry in CNT due to the wrapping of mannose dendrimer as the reason for this band gap opening which leads to metal-semiconductor transition in CNT. Thus, the wrapping of mannose dendrimer on CNT can change its electronic properties and can be used in the band gap engineering of CNT in future nanotechnology.
Thus, the works carried out here in this dissertation will help to address the problem of nanotube dispersion from the bundle geometry which will in turn help to use CNT for various applications in diverse fields.
Livres sur le sujet "Composite wrapping"
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Highway Innovative Technology Evaluation Center (U.S.). Guidelines for structural and durability evaluation of FRP composite column wrap systems for seismic retrofit of columns. Reston, VA : American Society of Civil Engineers, 2003.
Trouver le texte intégralChapitres de livres sur le sujet "Composite wrapping"
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Li, Hui, Yunfang Li, Yezeng He et Yanyan Jiang. « Helical Wrapping of Graphene Sheets and Their Self-Assembly into Core-Shelled Composite Nanostructures with Metallic Particles ». Dans Topological Modelling of Nanostructures and Extended Systems, 1–40. Dordrecht : Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-6413-2_1.
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« Wrapping with composite materials ». Dans Non-Metallic (FRP) Reinforcement for Concrete Structures, 611–18. CRC Press, 2004. http://dx.doi.org/10.1201/9781482271621-82.
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Deng, Yuhui, Frank Zhigang Wang et Na Helian. « Service Oriented Storage System Grid ». Dans Handbook of Research on Grid Technologies and Utility Computing, 126–35. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-184-1.ch013.
Texte intégralRésumé :
Storage Grid is a new model for deploying and managing the heterogeneous, dynamic, large-scale, and geographically distributed storage resources. This chapter discusses the challenges and solutions involved in building a Service Oriented Storage (SOS) Grid. By wrapping the diverse storage resources into atomic Grid services and federating multiple atomic Grid services into composite services, the SOS Grid can tackle the heterogeneity and interoperability. Peer-to-peer philosophy and techniques are employed in the SOS Grid to eliminate the system bottleneck and single point of failure of the traditional centralized or hierarchical Grid architecture, while providing dynamicity and scalability. Because Grid service is not designed for critical and real-time applications, the SOS Grid adopts Grid service to glue the distributed and heterogeneous storage resources, while using binary code to transfer data. The proposed methods strike a good balance among the heterogeneity, interoperability, scalability and performance of the SOS Grid.
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Sundararajan, P. R., et Molla Rafiquel Islam. « Poly(vinyl alcohol) ». Dans Polymer Data Handbook, 1116–29. Oxford University PressNew York, NY, 2009. http://dx.doi.org/10.1093/oso/9780195181012.003.0195.
Texte intégralRésumé :
Abstract Major Applications Paper and textile sizing, oxygen resistant films, adhesives, emulcifiers, colloid stabilizers, base/coatings for photographic films, food wrappings, desalination membranes, electroluminescent devices, and cement coatings, Gels and composites.
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El-Ghandour, A., et A. Abdelrahman. « Innovative three-sides wrapping technique for rectangular RC columns using CFRP sheets ». Dans FRP Composites in Civil Engineering - CICE 2004, 219–26. Taylor & Francis, 2004. http://dx.doi.org/10.1201/9780203970850.ch21.
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Bruce, W. A. « Comparison of fiber-reinforced polymer wrapping versus steel sleeves for repair of pipelines ». Dans Rehabilitation of Pipelines Using Fiber-reinforced Polymer (FRP) Composites, 61–78. Elsevier, 2015. http://dx.doi.org/10.1016/b978-0-85709-684-5.00004-7.
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Bennett, Peggy D. « Time to beware ». Dans Teaching with Vitality. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190673987.003.0052.
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When we are vulnerable, it’s time to be extra cautious. Physically or emotionally, there are times when we know we are not at our best. We may be in pain, fatigued, fearful, or just out of sorts. It is a “beware time.” Imagine yourself at your best, descending a set of stairs. You hop from step to step. You move quickly and confidently. You don’t even look at the steps. You don’t hold on to the banister. You are extremely confident and efficient. Now imagine yourself injured or in pain as you descend a set of stairs. You are cautious. You cling unsteadily to the banister for support. You move slowly, placing both feet on one step before you move to the next. You are tense as you hold tightly to the person you have asked to assist you. You don’t take your eyes off the danger, looking at nothing but the steps you need to traverse. You use all your diminished strength to keep from falling. Your heart is racing. We all have occasions to experience confident freedom and cautious fear. Like navigating the stairs when we are impaired, we need to know when we are especially vulnerable. Vulnerability can cloud our awareness and distract our attention. We can be prone to losing our patience, our temper, our composure. We follow a protocol for protecting a physical injury; protecting our spirit can be just as important. Our vulnerabilities wax and wane. Being aware helps us move into caution mode for a time, taking care to protect ourselves until it passes. Acknowledging your own “beware time” can be like wrapping yourself in a layer of protective padding or using a periscope to check out any risks hiding in the periphery. Your “beware time” may pass quickly or may amount to nothing. But naming it and being extra gentle with yourself can be a nice oasis of self- care and self- knowledge.
Actes de conférences sur le sujet "Composite wrapping"
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Parashar, Avinash, et Pierre Mertiny. « Challenges in Joining Thermoset Composite Piping ». Dans 2010 8th International Pipeline Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ipc2010-31297.
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The aim of this paper is to examine solutions and challenges related to joining thermoset composite piping. Fiber reinforced polymers (FRP) have been used in piping systems for more than 40 years. Higher specific mechanical properties and corrosion resistance of FRP make them a potential candidate for replacing metallic piping structures. Despite the advantages associated with FRP, their application is still limited due to, in part, unsatisfactory methods for joining composite subcomponents and inadequate knowledge of failure mechanism under different loading conditions. Adhesively bonded joints are attractive for many applications since they offer integrated sealing, minimal part count and do not require pipe extremities with complex geometries such as threads or bell and spigot configurations. So far, the majority of work reported in the technical literature on adhesively bonded pipe joints is concerned with lap joints employing wrapping techniques to produce overlap sleeve connections. More recently, a joining technique was proposed that replaces the wrapping technique with filament-wound overlap sleeve couplers that are adhesively bonded to the pipe extremities. In the present article, various joining techniques for FRP piping through adhesive bonding are discussed, and damage mechanisms under different loading conditions are examined.
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Parker, Anthony P., Edward Troiano et John H. Underwood. « Stresses Within Compound Tubes Comprising a Steel Liner and an External Carbon-Fiber Wrapped Laminate ». Dans ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-2277.
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There is increasing interest in techniques that permit weight reduction of thick cylinders, particularly gun barrels. The method examined within this paper involves the external wrapping of a carbon fiber-based laminate jacket around a steel liner. Various design options are examined, e.g. prior autofrettage of a steel liner followed by external tension wrapping and benign wrapping of a stress-free steel liner followed by autofrettage of the assembly. Outcomes include optimum overstrain and machining of the steel liner, identification of a potential ‘crushing’ failure mode due to radial compressive stresses and techniques for application of tension wrapping which optimize hoop stress within the composite jacket. Finally, possible combinations of fiber orientations are discussed.
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Wu, Hwai-Chung. « Confinement Efficiency of FRP Wrapping on Concrete ». Dans ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0203.
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Abstract A high fiber modulus is often believed to be the key element of a successful Fiber Reinforced Plastics (FRP) wrap for strengthening concrete structures. This demand for high fiber modulus, together with durability concern, lead to the choice of carbon, as used in many retrofitting applications. In this paper, such concept will be examined from a micromechanical consideration by taking account of mechanical interaction between FRP sheet and concrete. Concrete failure is initiated by wing crack propagation under compressive loads. An explicit relationship of the amount of confining pressure and FRP configuration (fiber type, architecture, and orientation), taking the interaction into account, is of critical importance for FRP performance optimization. The mechanical interaction dominates the composite behavior from the first bent-over point to the peak load in a load/displacement curve. The detailed interaction under compression is described, and unique insights obtained from the model are discussed in this paper.
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Yamamoto, Namiko, Nathan Wicks et Brian Wardle. « Wrapping and Through-Thickness Poisson Effects on Composite Plate and Shell Contact Laws ». Dans 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference. Reston, Virigina : American Institute of Aeronautics and Astronautics, 2005. http://dx.doi.org/10.2514/6.2005-1845.
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Browne, Alan L., Nancy L. Johnson et Mark E. Botkin. « Composite Crash Box : Roll Wrap Fabrication and Dynamic Axial Crush Performance ». Dans ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41143.
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A feature of many vehicles is a bolt-on, replaceable front end clip designed to protect the remaining structure in 0° to 30° frontal and offset crashes up to 15 km/hr (ECE-R42, European Danner (AZT), Allianze, VDS, or Thatcham Tests). The principle energy absorbing elements in such front clips are called crash or crush boxes. These are hollow cross section often tubular structures located between the bumper and the front ends of the lower rails. Previous studies of the dynamic axial crush response of carbon fiber reinforced composite tubes suggested that both the mass of the crash box and the amount of overhang of the front end clip could be reduced by switching from a metal to a carbon fiber reinforced composite crash box. The axial dimension of the crash box could theoretically be reduced because of the 20% reduction in stack-up exhibited by composite compared to metal tubular structures. The mass could theoretically be reduced because of the higher energy dissipation capability per unit mass of the carbon fiber composite and the shorter length that would be required. The initiative summarized in this paper was the roll wrapping portion of a one year program intended to prove out these benefits. Specifically, it encompassed the design, roll wrapping fabrication, and dynamic axial crush testing of a carbon fiber composite version of the crash box for a mid-size vehicle. All project goals were met. As first steps crush performance of the baseline Al crash box was determined and requirements were established for the geometry and crush force of the composite crash box, the needed crush force being 70 kN. To achieve the desired crush force levels while reducing mass by 20% compared to Al requires an SEA (specific energy absorption) on the order of 45. Crash box specimens manufactured with the roll wrapping process spanned a wide range of fiber architectures which were chosen based on findings of earlier crush tests of composite tubular specimens. Dynamic axial crush tests were then conducted on these specimens. Through these tests we were successful in identifying combinations of fiber type, fiber architecture, and tube wall thickness that simultaneously satisfied the multiple targets of high crush force, low stack-up (high crush efficiency), and reduced mass.
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Mitra, Aniruddha, Sirajus Salekeen et Mosfequr Rahman. « Fabrication of Polyurethane Based Fabric Composite Shaft and its Experimental Study Under Triple Point Bending ». Dans ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-88531.
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Semi-rigid urethane based fiber composite shafts are fabricated by high pressure injection molding process. The samples are made in Georgia Southern University’s laboratory where compressed air pressure is effectively used for this purpose. A special manufacturing process is suggested which can be used for mass production of these composites. This unique manufacturing technique creates a composite shaft with a core made of matrix material which is completely wrapped around by a woven fiber cloth with a very strong bonding between core and fibers. Three different types of woven fibers: fiber glass, Kevlar 49, and carbon fibers, are used. Triple point bending tests are carried out to test these three different types of composite samples and also samples made of only base or core material. During the test as the applied load is increased, a linear trend is observed between the load and mid-point deflection of the specimens up to a certain level. Higher load causes separation of fibers and core matrix and followed by local buckling of the separated fibers that are under compression region. This phenomenon brings down the bending stiffness of the composite significantly and it is quite pronounced in the load deflection curve diagram. Failure modes are observed to differ for each of these three types of composite and are discussed in details here. Composites with fiber glass wrapping are found to be the strongest among the three. Future work will involve determining the torsional and fatigue properties, and also the effect of fiber orientations on the mechanical properties of these composites.
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Browne, Alan L., et Nancy L. Johnson. « Dynamic Axial Crush Tests of Roll Wrapped Composite Tubes : Plug vs. Non-Plug Crush Initiators ». Dans ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-79158.
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This paper discusses the effects of the method of crush initiation on the dynamic axial crush response of roll wrapped composite tubes. This constitutes a portion of a successful fundamental study conducted at GM R&D of the dynamic axial crush of automotive rail-sized composite tubes reinforced variously with carbon fiber, Kevlar® and hybrid combinations of the two, and manufactured using roll wrapping techniques suitable for the low cost high volume needs of the automotive industry. All tubes were manufactured using roll wrapping from multiple layers of uni-directional thermoset prepreg with the uni-directional fabric plies being oriented at ± 15° with respect to the longitudinal axis of the tube. A total of 21 dynamic axial crush tests were conducted using a free flight drop tower facility. Tests spanned a range of tube geometries — circular and square with different wall and cross section dimensions with cored and uncored walls and differing numbers of plies — and a range of drop heights/impact velocities and drop masses. A general finding was that stable and progressive crush occurred at acceptable load levels in all of the roll-wrapped tubes that were tested for all methods of crush initiation that were considered — a 45° lead end bevel either alone, with a zero radius plug-type crush initiator, or with a 12.7 mm radius plug. The method of crush initiation was, however, found to be capable of producing major differences in the crush initiation force Fp, the displacement average crush force Fav(D), the specific energy absorption SEA, and the crush morphology. As examples, both the displacement average value of dynamic axial crush force and the value of SEA were changed by as much as a factor of eight by the method of crush initiation.
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Arif, Abul Fazal M., M. Anis et A. Al-Omari. « Performance of a Composite Repair System for Externally Corroded Metallic Pipe Using Numerical Model ». Dans ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36483.
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Traditionally, corroded pipelines with metal loss defects have been repaired by replacing the defective areas with metallic pipe segments or by welding on metallic sleeves. Considering the technical and economic advantages of composite materials, literature shows that these defects can be repaired or reinforced with a composite sleeve system. In these systems, epoxy filler is used to fill the corrosion defect followed by wrapping the piping segment with concentric coils of composite material. However several challenges need to be met to obtain the desired repair quality. The major considerations are surface preparation, reduction in operating pressure for the repair, the duration required (e.g. for curing of the composite material) for the composite repair to share the load from the pipe, and the most important is the in-field quality assessment and to ensure consistency between several repairs. In this work, a numerical model is developed to investigate the performance of composite repair systems and compare with the traditional metallic welded sleeve. The effect of fiber orientation, repair sleeve thickness, material and installation pressure have been studied. Results show the potential of composite repair system in replacing the existing welded metallic non-pressure containing sleeve for metallic pipelines.
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Ahmed, Rehan, Siti Haslina Mohd Ramli, Fadhlan B. A. Aziz et Rosman Arifin. « Effectiveness of Dynamic Response Spectroscopy and Microwave Inspection Technology for Substrate Pipe and Composite Wraps ». Dans International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21799-ms.
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Abstract This paper discusses in depth the technical differentiations of the Direct Response Spectroscopy (DRS) and Microwave (MW) system along with its capabilities of inspecting through various hard to inspect coatings and wraps, making the DRS and MW combo an ideal inspection technique. As with every technology, the limitations of the DRS and MW systems will also be covered to give an unbiased view in the technology selection. This paper will also course through the successful trial at one of PETRONAS operating onshore plants with the detailed result presentation concluding with the efficiency and cost effectiveness of employing the DRS and MW for inspection of composite wraps. The DRS and MW systems, both proprietary technologies developed by Sonomatic, are used in combination to assess the integrity of pipes and pipelines under composite overwrap repairs. These Non-Destructive Testing technique. are robust, reliable and possess the ability to inspect composite overwrap repairs and the piping substrate while online. The DRS is essentially an ultrasonic corrosion mapping technique that Measures steel WT with ±0.5 mm accuracy and identifies flaws in composite materials. It is engineered to excite the steel with low ultrasonic frequencies where conventional high frequency ultrasound could not penetrate. The MW measures depth of flaws in the wrapping materials identified by DRS inspection. It operates on very low power and is excellent on the inspection of non-conductive material.
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KRYSIAK, P. « Microstructural Analysis of Wound Composites with Considerations on the Fiber Winding Force ». Dans Quality Production Improvement and System Safety. Materials Research Forum LLC, 2023. http://dx.doi.org/10.21741/9781644902691-6.
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Abstract. The paper concerns issues related to the fabrication and microstructural analysis of carbon and glass fiber-reinforced epoxy composites. For the purposes of the tests, ring samples of carbon fiber and glass fiber were fabricated, each sample being made of the same amount of material. The rings were produced by circumferentially wrapping fibers onto a rigid core. During winding, the fiber tension was changed for each sample to investigate whether the amount and distribution of fibers in the composite depending on the force applied. The applied tension forces ranged from 18 to 138 N. In the next stage of tests, small fragments were cut out of the rings, cutting perpendicularly to the arrangement of fiber bundles. The cut elements were then embedded in epoxy resin. The microsections prepared in this were ground using a grinding disc with a gradation of 80 to 4000 and then polished, washed and dried. After these treatments, microscopic photos of the tested surfaces were taken. Observations were made using a NEOPHOT 32 microscope with an integrated camera and a KEYENCE VHX microscope. The volume fraction of voids and discontinuities in the matrix, as well as the volume fraction of fibers, were determined by measuring the percentage of the surface areas occupied by the appropriate components of the composite. On each cross-section of individual samples, photographs were taken in three planes parallel to the composite layers and three planes perpendicular to the fibers in the matrix system. The image analysis method was used for verification, in which it is assumed that the assessment of fiber distribution in a two-dimensional section is representative of its volumetric distribution. This method is mainly used to analyze the distribution of fibers with a constant cross-section. The most important conclusions from the conducted analyses allow the authors to state that in both composites the fibers in the matrix are highly packed and that there was no significant and noticeable effect of fiber tension during winding on the "packing" density of fibers in the composites.
Rapports d'organisations sur le sujet "Composite wrapping"
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Bailey, David M., Vincent F. Hock, P. A. Noyce et M. Restly. Polymer Composite Wrapping and Cathodic Protection System for Reinforced Concrete Piles in Marine Applications. Fort Belvoir, VA : Defense Technical Information Center, juin 2013. http://dx.doi.org/10.21236/ada582965.
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Automated Composite Column Wrapping. Purdue University, 2007. http://dx.doi.org/10.5703/1288284315877.
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