Dissertations / Theses: 'Fiber Composite Materials'

1

Bulsara, Vatsal N. "Effects of fiber spatial distribution and interphase on transverse damage in fiber-reinforced ceramic matrix composites." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/21429.

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2

Wu, Xiang. "Thermoforming continuous fiber reinforced thermoplastic composites." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/9383.

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3

Enemuoh, Emmanuel Ugochukwu. "Smart drilling of advanced fiber reinforced composite materials /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9998482.

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4

Veazie, David R. "Modeling of fiber reinforced composites incorporating distinct interface properties." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/17385.

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5

Perkins, Holly Lyn. "Air knife fiber spreading in composites manufacturing." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/19068.

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6

Pathak, Sayali V. "Enhanced Heat Transfer in Composite Materials." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1368105955.

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7

Razvan, Ahmad. "Fiber fracture in continuous-fiber reinforced composite materials during cyclic loading." Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-05042006-164536/.

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8

Lin, Shih-Yung. "Feasibility of fiber reinforced composite materials used in highway bridge superstructures." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/45894.

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Composite materials are considered here as structural materials of highway bridge superstructures. Bridge deck designs can be done according to AASHTO¹ specification and elastic design concepts.

In order to evaluate the feasibility of composites as structural materials of highway bridge superstructures, composite materials are compared not only to composite materials themselves but also to the most popular bridge structural materials, which are reinforced concrete and structural steel.

The AASHTO¹ HS2O-44 truck load is selected as the standard loading condition of all designs. Loads other than dead load and live load are not considered. Configurations of the bridges are different. Appropriate cross-section of girders are selected according to the material types. For fiber reinforced composite materials, box girder is used, for reinforced concrete, T-beam is selected; in addition, steel concrete composite section is another case.

Design methods are different from material to material. Reinforced concrete T-beam design is based on the 'Ultimate Strength Design' method. Steel concrete composite sections are designed according to the 'Load & Resistance Factor Design'. For composite materials, 'Elastic Design' is selected.

The results derived are as expected. Substantial weight saving is achieved by simply replacing concrete or steel with composite materials. This also results in many other advantages such as construction time, cost, foundation settlement and support requirements.

Master of Science

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9

Na, Gwang-Seok. "Load-displacement behavior of frame structures composed of fiber reinforced polymeric composite materials." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26699.

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Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Dr. Leroy Z. Emkin; Committee Co-Chair: Dr. Abdul-Hamid Zureick; Committee Member: Dr. Dewey H. Hodges; Committee Member: Dr. Kenneth M. Will; Committee Member: Dr. Rami M. Haj-ali. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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10

Hsu, Sheng-yuan. "On the prediction of compressive strength and propagation stress of aligned fiber-matrix composites /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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11

Vogler, Tracy John. "On the failure and post-failure of fiber composites in compression /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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12

Case, Scott Wayne. "Mechanics of Fiber-Controlled Behavior in Polymeric Composite Materials." Diss., Virginia Tech, 1996. http://hdl.handle.net/10919/30568.

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Modern durability and damage tolerance predictions for composite material systems rely on accurate estimates of the local stress and material states for each of the constituents, as well as the manner in which the constituents interact. In this work, an number of approaches to estimating the stress states and interactions are developed. First, an elasticity solution is presented for the problem of a penny-shaped crack in an N-phase composite material system opened by a prescribed normal pressure. The stress state around such a crack is then used to estimate the stress concentrations due to adjacent fiber fractures in a composite materials. The resulting stress concentrations are then used to estimate the tensile strength of the composite. The predicted results are compared with experimental values. In addition, a cumulative damage model for fatigue is presented. Modifications to the model are made to include the effects of variable amplitude loading. These modifications are based upon the use of remaining strength as a damage metric and the definition of an equivalent generalized time. The model is initially validated using results from the literature. Also, experimental data from APC-2 laminates and IM7/K3B laminates are used in the model. The use of such data for notched laminates requires the use of an effective hole size, which is calculated based upon strain distribution measurements. Measured remaining strengths after fatigue loading are compared with the predicted values for specimens fatigued at room temperature and 350Â°F (177Â°C).
Ph. D.

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13

Pierce, Matthew Ryan. "Microvascular Heat Transfer Analysis in Carbon Fiber Composite Materials." University of Dayton / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1280944914.

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14

Xu, Jian. "Rehabilitation of concrete highway bridge members using fiber-reinforced composites." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/20180.

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15

Patlapati, Ravinarayana Reddy Tejas. "Interlayer toughening of carbon-fiber/benzoxazine composite laminates." Thesis, California State University, Long Beach, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10264601.

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Carbon-fiber composites are increasingly employed in the Aerospace and Automotive industries owing to their lightweight and excellent mechanical properties. However, this class of material, when subjected to out-of-plane loads, is often susceptible to an internal damage in the form of delamination that can severely reduce its load bearing capacity. Several toughening methods including the implementation of thermoplastic materials are used to increase the damage tolerance of the polymer-matrix composites. In particular, non-woven thermoplastic veils, when used as interleaving materials between the plies in a composite structure, is extremely efficient at improving the interlaminar (delamination) fracture toughness and impact-resistance of composites. In addition, the toughening of the polymer matrix, if not adversely affecting the manufacturing process, can result in an increase in the toughness-related properties of composite laminates such as the resistance to micro-cracking under thermal-cycling conditions.

In this study, the effects of matrix toughening and interleaving of the composite with non-woven Polyamide (PA) veils on the Interlaminar Fracture Toughness (ILFT) of Carbon-fiber/Benzoxazine composites are investigated. Formulated Benzoxazine (BZ) resins in non-toughened and toughened variants along with several non-woven PA veils with different melt temperatures are used to manufacture composite laminates through the Vacuum Assisted Resin Transfer Molding (VARTM) process. The ILFT of composites is measured by obtaining the resistance to crack propagation in the interlayer under tensile forces (Mode-I ILFT) or shear forces (Mode-II ILFT). The critical strain energy release rate (Gc) recorded during interlaminar fracture gives a measure of the ILFT of a composite.

The laminates interleaved with the PA veils show an increase of nearly 50% for the Mode-I crack initiation (GIc initiation), regardless of the melt temperature of the PA veils. The Mode-I crack propagation (GIc propagation) of the laminate increases by using the PA veils with melt temperatures lower than the cure temperature of the BZ resin.

In the Mode-II ILFT (GIIc) tests, the laminates interleaved with the PA veils show a significant impact on the GIIc values, as increases of nearly 170% are observed. A strong correlation between PA melt temperatures and the GIIc values is noted. The greatest GIIc values are noted when the melt temperature of the PA veil is greater than the cure temperature of the BZ resin.

The matrix toughness plays a significant role in affecting the GIc values. The laminates manufactured with the toughened BZ resin result in the greatest increase in the GIc values. In contrary, the use of the toughened BZ resin does not result in an improvement in the GIIc values.

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16

Bocchieri, Robert Thomas. "Time-dependent deformation of a nonlinear viscoelastic rubber-toughened fiber composite with growing damage /." Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3008280.

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17

Jiang, Mingxiao. "Scale and boundary conditions effects in fiber-reinforced composites." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/16373.

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18

Yang, Bing. "Bending, compression, and shear behavior of woven glass fiber/epoxy composites." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/8710.

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19

Hong, Yong. "Fatigue and Fracture of the FRP-Wood Interface: Experimental Characterization and Performance Limits." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/HongY2003.pdf.

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20

Knott, Tamara Wright. "Effect of fiber morphology on composite properties." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/44684.

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The effect of the cylindrically orthotropic morphology known to exist in graphite fibers on the effective properties of a composite material was studied using the composite cylinder assemblage model. The cylindrical orthotropy of the fibers was found to have no effect on the properties of a composite with purely orthotropic fibers. For fibers with a transversely isotropic core both the size of the core and the morphology of the sheath were found to have an effect on the composite properties.

The stress states resulting in the composite cylinder for axiai, radial, axiai shear, and thermal loads were examined. Singular stresses were observed to occur at r=0 in some fibers in some load conditions. The presence of a transversely isotropic core, which must exist in a real fiber, removed this singularity.

The strength of the composite cylinder was found to depend on uÌ ber morphology. The size of the transversely isotropic core within the uÌ ber also affected the strength. The strength of the uÌ ber increased with increasing transversely isotropic core size in some instances. In general, for axiai loading failure is expected to be caused by fiber breakage. For radial, axiai shear, and thermal loading the failure mode is uÌ ber splitting.

Master of Science

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21

Park, Jin Young. "Pultruded composite materials under shear loading." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/32865.

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22

Smulski, Stephen John. "Flexural behavior of a glass fiber reinforced wood fiber composite." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/53596.

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The static and dynamic flexural properties of a wood fiber matrix internally reinforced with continuous glass fibers were investigated. When modelled as a sandwich composite, the static flexural modulus of elasticity (MOE) of glass fiber reinforced hardboard could be successfully predicted from the static flexural MOE of the wood fiber matrix, and the tensile MOE and effective volume fraction of the glass fiber reinforcement. Under the same assumption, the composite modulus of rupture (MOR) is a function of the reinforcement tensile MOE and effective volume fraction, and the matrix stress at failure. The composite MOR was predicted on this basis with limited success. The static flexural modulus of elasticity, dynamic modulus of elasticity, and modulus of rupture of glass fiber reinforced hardboard increased with increasing effective reinforcement volume fraction. The logarithmic decrement of the composite decreased with increasing effective reinforcement volume fraction. Excellent linear correlation found among flexural properties determined in destructive static tests and nondestructive dynamic tests demonstrated the usefulness of dynamic test methods for flexural property evaluation. The short-term flexural creep behavior of glass fiber reinforced hardboard was accurately described by a 4-element linear viscoelastic model. Excellent agreement existed between predicted and observed creep deflections based on nonlinear regression estimates of model parameters.
Ph. D.

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23

Elouaer, Abdelmonem. "Contribution à la compréhension et à la modélisation du comportement mécanique de matériaux composites à renfort en fibres végétales." Thesis, Reims, 2011. http://www.theses.fr/2011REIMS003/document.

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L’industrie des matériaux composites ne cesse d’évoluer et de croître en mettant en place de nouveaux matériaux et de nouvelles technologies. En substitution des matériaux d’origine fossile que les matériaux d’origine naturelles (et surtout végétales) commencent à voir le jour. C’est dans ce contexte que notre travail de recherche est proposé. Il s’intéresse à la caractérisation du comportement mécanique d’un composite à matrice Polypropylène, renforcé avec des fibres de Chanvre et du bois de Chanvre (Chènevotte). Les différents moyens et techniques de caractérisation, utilisés par la présente étude, ont montré que ces nouveaux matériaux sont dotés de propriétés, en particulier mécaniques, de haut niveau, qui viennent rivaliser avec celles des autres composites classiques à base de fibres de verre et de carbone.Les essais expérimentaux en statique et de fatigue, ont révélé beaucoup de détails en comparaison avec d’autres matériaux composites. Ces informations ont permis de créer une sorte de base de données qui pourra servir de référence pour d’autres composites de la même famille à base de fibres végétales. Ainsi, des mécanismes d’endommagement ont été mis en évidence grâce aux essais mécaniques (traction monotone, charge-décharge, …) associés à des observations microscopiques (Microscope Electronique à Balayage), et à des outils de détection du dommage basés sur l’émission acoustique. Par le biais de cette technique, nous avons pu apprécier la qualité et l’importance de l’interface fibre/matrice qui est un paramètre fondamental pour la présente étude et pour la détermination de la loi de comportement du composite.La modélisation micromécanique a été intégrée dans ce travail de thèse, grâce au modèle de Mori-Tanaka. Le comportement des matériaux à l’endommagement n’a pas été pris en considération ; seule l’élasticité a été étudiée. A l’aide de ce modèle, nous avons pu remonter aux propriétés intrinsèques des constituants (le module d’élasticité longitudinale des renforts: Chanvre et Chènevotte)
The composites industry continues to evolve and grow by developing new materials and new technologies. Replacing fossil materials by materials with natural origin (especially vegetable) seems to be one of the most promising. In this context our research is proposed. It is interested to characterize the mechanical behavior of a polypropylene matrix composite reinforced with fibers of Hemp and Wood of Hemp (Chenevotte). The various means and characterization techniques used in this study showed that these new materials have interesting mechanical properties, coming rival those of other conventional composites based on carbon and glass fibers.The experimental static and fatigue tests have revealed many details in comparison with other composite materials. The information help creates a database that can serve as reference for other composites of the same family and vegetable fibers. Mechanisms of damage have been highlighted through mechanical tests (tensile monotonous charge-discharge …) associated with microscopic observations (Scanning Electron Microscope), and tools for damage detection based on emission acoustics. Thanks to this technique, we could improve the quality of the interface fiber / matrix which is a basic parameter for this study and for determining the behavior of composite.Micromechanical modeling has been integrated in this thesis, through the Mori-Tanaka model. The behavior of materials during damage has not been taken into account: only the elasticity has been studied. Using this model, we were able to trace the intrinsic properties of the constituents (the longitudinal modulus of elasticity of the reinforcements: Hemp and Chenevotte)

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Wasik, Thomas. "Effect of fiber volume fraction on fracture mechanics in continuously reinforced fiber composite materials." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001163.

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25

Bache-Wiig, Jens, and Per Christian Henden. "Individual fiber segmentation of three-dimensional microtomograms of paper and fiber-reinforced composite materials." Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2005. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9268.

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The structure of a material is of special significance to its properties, and material structure has been an active area of research. In order to analyze the structure based on digital microcopy images of the material, noise reduction and binarization of these images are necessary. Measurements on fiber networks, found in paper and wood fiber - reinforced composites, require a segmentation of the imaged material sample into individual fibers. The acquisition process for modern X-ray absorption mode micro-tomographic images is described. An improved method for the binarization of paper and fiber-reinforced composite volumes is suggested. State of the art techniques for individual fiber segmentation are examined and an improved method is suggested. Software tools for the mentioned image processing tasks have been created and made available to the public. The orientation distribution of selected paper and composite samples was measured using these tools.

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26

Schneider, Christof. "Recyclable self-reinforced ductile fiber composite materials for structural applications." Doctoral thesis, KTH, Lättkonstruktioner, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174131.

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Lightweight structures in vehicles are a proven way to reduce fuel consumption and the environmental impact during the use. Lower structural weight can be achieved by using high performance materials such as composites or using the material efficiently as a sandwich structure. Traditional composite materials such as carbon or glass fiber reinforced polymers have high weight specific mechanical properties but are inherently brittle and expensive. They consist of at least two different materials making recycling a difficult endeavor.The best composite material would have good weight specific properties and is ductile, cheap and comprises of a reinforcement and matrix material based on the same recyclable material making recycling easy. In self-reinforced polymer (SrP) composite materials, reinforcing fibers and matrix material are based on the same recyclable thermoplastic polymer making recycling to a straightforward process. SrP composite materials are ductile, inexpensive and have a high energy absorption potential. The aim of this thesis is to investigate the potential of SrP composites in structural applications. Firstly, the quasi-static and dynamic tensile and compression properties of a self-reinforced poly(ethylene terephthalate) (SrPET) composite material are investigated confirming the high energy absorption potential. Sandwich structures out of only SrPET with a lattice core are manufactured and tested in quasi-static out-of-plane compression showing the potential of SrPET as core material. Corrugated sandwich structured out of only SrPET are manufactured and tested in out-of-plane compression over a strain rate range10−4 s−1 - 103 s−1. The corrugated SrPET core has similar quasi-static properties as commercial polymeric foams but superior dynamic compression properties. Corrugated sandwich beams out of only SrPET are manufactured and tested in quasi-static three-point bending confirming the high energy absorption potential of SrPET structures. When comparing the SrPET beams to aluminum beams with identical geometry and weight, the SrPET beams shows higher energy absorption and peak load. The experimental results show excellent agreement with finite element predictions. The impact behaviorof corrugated SrPET sandwich beams during three-point bending is investigated. When comparing SrPET sandwich beams to sandwich beams with carbon fiber face sheets and high performance thermoset polymeric foam with the same areal weight, for the same impact impulse per area, the SrPET shows less mid-span deflection.

QC 20151012

ECO2

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27

Timmerman, John Francis. "Characterization of cryogenic microcracking in carbon fiber/epoxy composite materials /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/9910.

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28

Tedeschi, Lorenzo. "Fiber reinforced polymer composite materials for bridge construction and retrofitting." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3997/.

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29

Gupta, Arnab. "Monitoring Progressive Damage Development in Laminated Fiber Reinforced Composite Materials." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78766.

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With increasing applications of composite materials, their health monitoring is of growing importance in engineering practice. Damage development in composite materials is more complex than for metallic materials, because in composite materials (a) multiple damage modes are simultaneously in play, and (b) individual 'damage events' that occur throughout a component's service life may neither noticeably affect its performance, nor suggest future failure. Therefore, informed health monitoring of composite components must include monitoring and analysis of their health state throughout their service life. A crucial aspect of the health monitoring process of composites is the development of tools to help with this goal of understanding the health state of composites throughout their life. This knowledge can lead to timely anticipation of future failure in composite components, and advance the state of current technology. One, timely maintenance can be planned in advance. Two, each component's service life can be determined based on its individual health information, rather than empirical statistics of previously failed components. This dissertation develops such tools and methods. Composite specimens of multiple ply-layups are subjected to tensile loading schemes until failure. Pencil Lead Breaks (PLBs) are used to simulate Acoustic Emission sources and generate acoustic waves that are acquired by installed piezoelectric sensors. A numerical method to estimate the arrival of wave modes from ultrasonic signals is presented. Methods are also presented that utilize PLB signals to indicate approaching failure of specimens under monotonic as well as cyclic loading. These processes have been developed prioritizing simplicity and ease-of-execution, to be adapted for practical deployment.
Ph. D.

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30

Han, Ning. "Hydrogel-Electrospun Fiber Mat Composite Materials for the Neuroprosthetic Interface." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1292881087.

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31

Thibodeau, Elisabeth Gabrielle. "Static and Fatigue Fracture Characterization of Primary and Secondary Bonded Woven E-Glass Composites." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/ThibodeauEG2007.pdf.

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32

Peters, Sarah June. "Fracture Toughness Investigations of Micro and Nano Cellulose Fiber Reinforced Ultra High Performance Concrete." Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/PetersSJ2009.pdf.

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33

Garcia, Jorge David Aveiga. "A delamination propagation model for glass fiber reinforced laminated composite materials." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18148/tde-31072018-143609/.

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The employment of composite materials in the aerospace industry has been gradually considered due to the fundamental lightweight and strength characteristics that these type of materials offer. The science material and technological progress that has been reached, matches perfectly with the requirements for high-performance materials in aircraft and aerospace structures, thus, the development of primary structure elements applying composite materials became something very convenient. It is extremely important to pay attention to the failure modes that influence composite materials performances, since, these failures lead to a loss of stiffness and strength of the laminate. Delamination is a failure mode present in most of the damaged structures and can be ruinous, considering that, the evolution of interlaminar defects can carry the structure to a total failure followed by its collapse. Different techniques are usually adopted to accurately predict the behavior of damaged structures but, due to the complex nature of failure phenomena, there is not an established pattern. The present research project aims to develop a delamination propagation model to estimate a progressive interlaminar delamination failure in laminated composite materials and to allow the prediction of material\'s degradation due to the delamination phenomenon. Experimental tests assisted by ASTM Standards were performed to determine material\'s parameter, like the strain energy release rate, using GFRPs laminated composites. The delamination propagation model proposed was implemented as subroutines in FORTRAN language (UMAT-User Material Subroutine) with formulations based on the Fracture Mechanics. Finally, the model was compiled beside with the commercial Finite Element program ABAQUSTM.
O emprego de materiais compósitos na indústria aeroespacial tem sido gradualmente utilizado devido às suas características fundamentais, como peso leve e alta rigidez, que este tipo de material oferece. Tanto a ciência do material como o desenvolvimento tecnológico que se tem logrado, possibilitaram que estes materiais cumprissem com os requisitos de desempenho para aplicações em estruturas aeronáuticas e aeroespaciais, por tanto, o desenvolvimento de elementos de estruturas primárias usando materiais compósitos, passou a ser muito conveniente. É de extrema importância prestar atenção aos modos de falha que comprometem a performance dos materiais compósitos, uma vez que, estas falhas levam a uma perda de resistência e rigidez do laminado. A delaminação é um modo de falha presente na maioria de estruturas danificadas e pode ser desastroso, considerando que, a evolução dos defeitos interlaminares podem levar a estrutura a falhar seguido pelo colapso estructural. Diferentes técnicas são geralmente adotadas para prever, de maneira correta, o comportamento de estruturas danificadas, porém, devido à natureza complexa do fenômeno de falha, não existe um padrão estabelecido. O presente trabalho de pesquisa visa desenvolver um modelo de delaminação e de propagação da delaminação para estimar a evolução da falha interlaminar em materiais compósitos laminados e permitir a predição do comportamento do material com a evolução da delaminação. Ensaios experimentais auxiliados por normas ASTM foram realizados para determinar parâmetros do material, tais como, as taxas de liberação de energia de deformação, usando materiais compósitos laminados de matriz polimérica reforçada com fibra de vidro. O modelo de propagação da delaminação proposto, foi implementado como uma sub-rotina em linguagem FORTRAN (UMAT – User Material) com formulações baseadas na Mecânica da Fratura. Finalmente, o modelo foi compilado com o software comercial de Elementos Finitos, ABAQUSTM.

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Herzog, Benjamin J. "Characterization of the Void Content of Fiber Reinforced Polymer (FRP) Composite Materials Fabricated by the Composites Pressure Resin Infusion System (COMPRIS)." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/HerzogBJ2004.pdf.

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Xu, Ying. "Detection of delamination in composites with fiber optic sensor /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202004%20XU.

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Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2004.
Includes bibliographical references (leaves 194-209). Also available in electronic version. Access restricted to campus users.

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May, Russell G. "Miniature Fiber Optic Viscoelasticity Sensor for Composite Cure Monitoring." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30628.

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The most promising strategy for reducing the cost of manufacturing polymer matrix composites while improving their reliability is the use of sensors during processing to permit control of the cure cycle based on measurements of the material's internal state. While sensors have been demonstrated that infer the material state indirectly through measurements of acoustic impedance, electrical impedance, or refractive index, sensors that directly measure parameters critical to composite manufacturing, such as resin rheology and resin hydrostatic pressure, would improve characterization of thermoset resins during cure. Here we describe the development of a multifunctional fiber optic sensor that may be embedded in a composite part during lay-up to monitor the state of the polymer matrix during processing. This sensor will output quantitative data which will indicate the viscoelasticity of the thermoset matrix resin. The same sensor will additionally function as a strain sensor following fabrication, capable of monitoring residual strains due to manufacturing or in-service internal strains.
Ph. D.

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37

Scott, David William. "Short- and long-term behavior of axially compressed slender doubly symmetric fiber-reinforced polymeric composite members." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/19276.

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38

Zalameda, Joseph Nomasa. "Full Field Nondestructive Techniques for Imaging Composite Fiber Volume Fraction." W&M ScholarWorks, 1996. https://scholarworks.wm.edu/etd/1539626040.

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39

Bundy, Bryan Charles. "Use of pultruded carbon fiber / epoxy inserts as reinforcement in composite structures." Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/bundy/BundyB0506.pdf.

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40

Babamohammadi, Sajjad. "Mechanical Assessment of Fiber Reinforced Composite Hollow Circular Beams." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.

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This thesis presents a study on fiber reinforced hollow beams. The theoretical background is based on published works and some extensions to the present researches. For some, simple, cases exact solutions are made available, however hollow composite beams have to be studied using 3D modeling in order to capture their actual anisotropic behavior. At first, we start to investigate if we have enough information to successfully design a structure using FRP materials. Then after studying some published works in this field, we understood that there is a lack of some important details. We tried to fill this void by first understanding the behavior of FRP beams and prepare a fast and easy way for engineers to use these composite beams and design structures. To do that, we used existing analytical methods. Although analytical, these methods are limited for studying fiber reinforced beams. Thus, a new approach is here presented based on an equivalent 3D shell model which is used to defined a 3D finite element beam element for frame structural analysis. This approach is simple and clearly considers the anisotropy inherited in such profiles. Applications of this procedure are given which show the quality of the present results and the advantages of using composite beams with respect to classical steel beams in civil applications.

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Batarseh, Melanie Turkett. "Formation of anisotropic hollow fiber membranes via thermally induced phase separation /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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Anbarasu, Arungalai. "Characterization of defects in fiber composites using terahertz imaging." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24632.

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Hegg, Meredith Michelle. "Exact Relations and Links for Fiber-Reinforced Elastic Composites." Diss., Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/164322.

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Mathematics
Ph.D.
Predicting the effective elastic properties of a composite material based on the elastic properties of the constituent materials is extremely difficult, even when the microstructure is known. However, there are cases where certain properties in constituents always carry over to a composite, regardless of the microstructure of the composite. We call such instances exact relations. The general theory of exact relations allows us to find all of these instances in a wide variety of contexts including elasticity, conductivity, and piezoelectricity. We combine this theory with ideas from representation theory to find all exact relations for fiber-reinforced polycrystalline composites. We further extend these ideas to the concept of links. When two composites have the same microstructure but different constituent materials, their effective tensors may be related. We use the theory of exact relations to find such relations, which we call links. In this work we describe a special set of links between elasticity tensors of fiber-reinforced polycrystalline composites. These links allow us to generalize certain results from specific examples to generate new information about this widely-used class of composites. In particular, we apply the link to obtain information about composites made from two transversely isotropic materials and polycrystals made from one orthotropic material.
Temple University--Theses

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Ketterer, Justin M. "Fatigue crack initiation in cross-ply carbon fiber laminates." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29697.

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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2010.
Committee Chair: Dr. Steve Johnson; Committee Member: Dr. Jianmin Qu; Committee Member: Dr. Rick Neu. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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Rast, Joshua David. "Characterizing the fatigue damage in non-traditional laminates of carbon fiber composites using radiography." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28262.

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Johnson, Timothy Michael. "Strain Monitoring of Carbon Fiber Composite with Embedded Nickel Nano-Composite Strain Gage." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2622.

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Carbon fiber reinforced plastic (CFRP) composites have extensive value in the aerospace, defense, sporting goods, and high performance automobile industries. These composites have huge benefits including high strength to weight ratios and the ability to tailor their properties. A significant issue with carbon fiber composites is the potential for catastrophic fatigue failure. To better understand this fatigue, there is first a huge push to measure strain accurately and in-situ to monitor carbon fiber composites. In this paper, piezoresistive nickel nanostrand (NiNs) nanocomposites were embedded in between layers of carbon fiber composite for real time, in situ strain monitoring. Several different embedding methods have been investigated. These include the direct embedding of a patch of dry NiNs and the embedding of NiNs-polymer matrix nanocomposite patches which are insulated from the surrounding carbon fiber. Also, two different polymer matrix materials were used in the nanocomposite to compare the piezoresistive signal. These nanocomposites are shown to display repeatable piezoresistivity, thus becoming a strain sensor capable of accurately measuring strain real time and in-situ. This patch has compatible mechanical properties to existing advanced composites and shows good resolution to small strain. This method of strain sensing in carbon fiber composites is more easily implemented and used than other strain measurement methods including fiber Bragg grating and acoustic emissions. To show that these embedded strain gages can be used in a variety of carbon fiber components, two different applications were also pursued.

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Zhang, Xiefei. "Studies on Single Wall Carbon Nanotube and Polymer Composite Films and Fibers." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/7610.

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Single wall carbon nanotubes (SWNT) have been extensively studied over the last decade due to their excellent comprehensive properties for a variety of applications. This study is focused on the applications of SWNTs as reinforcement for polymer matrices. Due to van der Waal interactions, SWNTs form bundles of about 30 nm diameters. In order to take full advantage of the SWNT mechanical properties, SWNT must exfoliate or at least disperse in small diameter bundle size. Optical microscopy and SEM only give qualitative information of dispersion. Quantitative characterization through TEM or AFM can be time consuming in order to get statistical result. In this study, simple method is developed to quantitatively estimate the size of SWNT bundle in dispersion based on the geometry controlled electrical percolation behavior. The SWNTs can be dispersed /exfoliated via PVP wrapped SWNT aqueous dispersion assisted by surfactants such as sodium dodycel sulfate. PVA / SWNT composite films prepared through PVP wrapped SWNTs exhibit improved mechanical properties as well as the evidence of load transfer from the polymer matrix to the SWNT as monitored by the Raman spectroscopy. SWNT can also be well dispersed into PVA/DMSO/H2O solution. Gel spinning of PVA/SWNT composite fiber has been successfully carried out with improved mechanical properties. Functionalized tubes can be used to enhance SWNT dispersion and exfoliation. Oxidation in strong acids is one method used for functionalizing nanotubes. SWNTs have been functionalized in nitric acid. The structure and properties of films (buckypaper) processed from nitric acid functionalized tubes have been studied exhibiting high tensile strength and high electrical conductivity. Nitric acid treatment results in selective degradation of the small diameter tubes.

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Fredheim, Rasmus. "Infrared Curing of Glass Fiber Composite Tube : Optimization of the curing cycle." Thesis, Karlstads universitet, Avdelningen för maskin- och materialteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-85466.

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This thesis has investigated the possibility of optimizing curing time by changing the energy source from a conventional oven to infrared radiation (IR) and if it is possible to achieve similar results as the company's current production of glass fiber composite tubes. Many different parameters (time, temperature, heating rate, and rotation speed) might influence a cured composite tube's properties. Reduced factorial experiments were conducted to test all these parameters cost-efficient where each parameter was tested at a high and low level. However, every possible combination was not investigated. Temperature measurements during the curing cycles, energy calculations, three-point bending, and differential scanning calorimetry analysis were conducted to compare the two different curing methods, hot air and IR curing. The current production flexural strength and glass transition temperature (Tg) have acted as benchmark values that the tubes cured with IR would have to reach to be considered a reliable manufacturing method. Differential scanning calorimetry (DSC) analyses were conducted to measure the Tg and three-point bending to determine the flexural strength. Due to that no standard exist for three-point bending of composite tubes, an in-house method was created and verified with a finite element simulation in Abaqus, to measure the flexural strength. The simulated reaction force was circa 76.9% of the measured force at the same displacement during the three-point bending test of the tubes. The simulation found that the stress concentration did occur at the same locations as the fracture occurred in the three-point bending test. The temperature difference between the top of the laminate and the core was close to zero degrees for the current production by hot air in a thermal oven. A more significant temperature difference between the core and top of the laminate was found during curing with IR. However, a higher rotation speed was found to create a more evenly temperature distribution in the composite. No clear correlation between the Tg and the flexural strength was found, as the literature suggests while comparing each test cured with IR. Nevertheless, by comparing every test cured with IR with the current production of the tube, it was determined that a lower Tg could cause a lower flexural strength. However, the lower flexural strength for the tubes cured by IR could also be explained by the temperature difference found between the core temperature and the top of the laminate during the curing process. The reduced factorial experiments showed that it was possible to reach similar properties by curing with IR and reducing the curing time by 69.3%. Time and the combination of time and temperature were found to affect the result when it comes to the glass transition temperature. Regarding flexural strength, no parameters were found to impact the outcome. By investigating the time and temperature further, the curing time could be reduced to 71.3% compared with the current production and still achieve similar properties. Nevertheless, the energy use for curing with IR was found to require 8.3 times more than the current production.

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Ozcan, Soydan. "Microstructure-property-performance relationships of c-fiber-reinforced carbon composite friction materials /." Available to subscribers only, 2008. http://proquest.umi.com/pqdweb?did=1686179081&sid=4&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Thesis (Ph. D.)--Southern Illinois University Carbondale, 2008.
"Department of Engineering Science." Keywords: Carbon composite, Friction materials, Carbon-fiber reinforcement Includes bibliographical references (p. 106-115). Also available online.

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Patterson, Forrest T. "Theoretical analysis of small crack growth in fiber-reinforced ceramic composite materials." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/38010.

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Dissertations / Theses on the topic 'Fiber Composite Materials'

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