Дисертації з теми "CNF/Epoxy Glass Fiber"
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Chen, Yu. "Finite element micromechanical modeling of glass fiber/epoxy cross-ply laminates." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0008/MQ60110.pdf.
Повний текст джерелаYang, Bing. "Bending, compression, and shear behavior of woven glass fiber/epoxy composites." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/8710.
Повний текст джерелаAussawasathien, Darunee. "ELECTROSPUN CONDUCTING NANOFIBER-BASED MATERIALS AND THEIR CHARACTERIZATIONS: EFFECTS OF FIBER CHARACTERISTICS ON PROPERTIES AND APPLICATIONS." Akron, OH : University of Akron, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1145050541.
Повний текст джерела"May, 2006." Title from electronic dissertation title page (viewed 10/11/2006) Advisor, Erol Sancaktar; Committee members, James L. White, Kyonsuku Min, Darrell H. Reneker, Wieslaw Binienda; Department Chair, Sadhan C. Jana; Dean of the College, Frank N. Kelley; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
Magrini, Michael A. "Fiber reinforced thermoplastics for ballistic impact." Birmingham, Ala. : University of Alabama at Birmingham, 2010. https://www.mhsl.uab.edu/dt/2010m/magrini.pdf.
Повний текст джерелаBilyeu, Bryan. "Characterization of Cure Kinetics and Physical Properties of a High Performance, Glass Fiber-Reinforced Epoxy Prepreg and a Novel Fluorine-Modified, Amine-Cured Commercial Epoxy." Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc4437/.
Повний текст джерелаBozkurt, Emrah Tanoğlu Metin. "Mechanical and thermal properties of non-crimp glass fiber reinforced composites with silicate nanoparticule modified epoxy matrix/." [s.l.]: [s.n.], 2006. http://library.iyte.edu.tr/tezler/master/makinamuh/T000517.pdf.
Повний текст джерелаKeywords: polymer composites, Nanoparticles, glass fiber, mechanical properties, thermal properties. Includes bibliographical references (leaves 75-79).
Totten, Kyle. "Determination of the tensile strength of the fiber/matrix interface for glass/epoxy & carbon/vinyl ester." Thesis, Florida Atlantic University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10096031.
Повний текст джерелаThe tensile strength of the fiber/matrix interface was determined through the development of an innovative test procedure. A miniature tensile coupon with a through-thickness oriented, embedded single fiber was designed. Tensile testing was conducted in a scanning electron microscope (SEM) while the failure process could be observed. Finite element stress analysis was conducted to determine the state of stress at the fiber/matrix interface in the tensile loaded specimen, and the strength of the interface. Test specimens consisting of dry E-glass/epoxy and dry and seawater saturated carbon/vinylester 510A were prepared and tested. The load at the onset of debonding was combined with the radial stress distribution near the free surface of the specimen to reduce the interfacial tensile strength (σi). For glass/epoxy, σi was 36.7±8.8 MPa. For the dry and seawater saturated carbon/vinylester specimens the tensile strengths of the interface were 23.0±6.6 and 25.2±4.1 MPa, respectively. The difference is not significant.
Ertekin, Ayca. "Analysis of Wetting, Flow and End-use Properties of Resin Transfer Molded Nanoreinforced Epoxy-glass Fiber Hybrid Composites." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1203418277.
Повний текст джерелаAl-Edhari, Mohammed F. "The Influence of Varying Fiber Stacking Sequence on the Tensile, Impact, and Water Absorption Properties of Unidirectional Flax/E-Glass Fiber Reinforced Epoxy Composite." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/6862.
Повний текст джерелаPapangelou, Christopher G. "Material Properties and Volumetric Porosity of Biomaterials for Use in Hard Tissue Replacement." Scholar Commons, 2005. https://scholarcommons.usf.edu/etd/808.
Повний текст джерелаEmbley, Michael D. "Damage Tolerance of Buckling-Critical Unidirectional Carbon, Glass,and Basalt Fiber Composites in Co-Cured Aramid Sleeves." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/3185.
Повний текст джерелаCoignac, Bruno. "Lois d'écoulement et endommagement en chargement statique ou cyclique d'un multimatériau "composite (verre/epoxy)-cuivre" : Etude expérimentale et modelisation." Besançon, 1988. http://www.theses.fr/1988BESA2024.
Повний текст джерелаSubagio, Bambang Sugeng. "Contribution à la modélisation de l'endommagement de fatigue en flexion dans les matériaux composites unidirectionnels." Ecully, Ecole centrale de Lyon, 1987. http://www.theses.fr/1987ECDLA008.
Повний текст джерелаNesa, Daniel. "Etude de la fissuration d'un composite unidirectionnel verre-résine." Paris, ENMP, 1987. http://www.theses.fr/1987ENMP0093.
Повний текст джерелаLI, SHI-TENG, and 李士騰. "Glass fiber reinforced polyurethane / epoxy graft interpenetrating polymer networks." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/25473227132164137855.
Повний текст джерелаWang, Chia-Hung, and 王嘉鴻. "Research on the putrusion of glass fiber reinforced brominated epoxy composites." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/04661920351673936515.
Повний текст джерелаLiu, Jin-Wei, and 劉晉瑋. "Optimization of novel epoxy/glass fiber nanocomposites utilizing experimental design method." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/64168670942589251619.
Повний текст джерела國立勤益科技大學
化工與材料工程系
99
In this study, novel nanocomposites are preparation and characterization. The Taguchi experimental design methodology is used to optimize the composition of a nanopowders/glass fiber epoxy resin material comprising nano-alumina, nano-silica, carbon black nanoparticle, epoxy resin, glass fiber and diluent. The effect of nanopowders and diluent addition on the corrosion resistance, thermal properties, and mechanical properties of the various samples are then observed. The results show that the addition of nanopowders will affect the properties of glass fiber/epoxy composites, resulting in thermal stability, corrosion resistance, glass transition temperature, hardness, storage modulus increased. Overall, that nanocomposite comprising 2 wt.% nano-Al2O3, 2 wt.% nano-SiO2, and 2 wt.% carbon black nanoparticle reduced the thermal expansion coefficient (α1) by 17.55% and increased the thermal decomposition temperature by 5.84% compared to that of the sample with no nanopowders. That nanocomposite comprising 2 wt.% nano-Al2O3, 2 wt.% nano-SiO2, 2 wt.% carbon black nanoparticle , and 3.75 wt.% diluent has the best storage modulus ,water and corrosion resistance. The experimental data generated in the Taguchi trials are processed using a regression analysis technique in order to derive analytical formulae relating the composition of the composite samples to their mechanical, thermal and corrosion properties. It is shown that the results obtained using the analytical formulae are in good agreement with the experimental observations. Thus, the derived formulae provide a quick and convenient means of predicting the mechanical and thermal response of glass fiber/ epoxy nanocomposites with a known composition without the need for experimental investigation.
顏俊成. "Research on pultrusion of glass fiber reinforced blocked polyurethane modified epoxy resins." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/70490001963271276713.
Повний текст джерела中國文化大學
材料科學與製造研究所
87
ABSTRACT The reserch present a proprietary process developed to manufacture pultruded blocked polyurethane modified epoxy resin composites in order to improve the impact strength of pultruded epoxy composites. The effect of processing parameters on the mechanical properties of pultruded glass fiber reinforced epoxy/blocked PU composites has been studied. Processing parameters include die temperature, pulling rate, postcure temperature and time, filler type and content, and fiber content. From the viscosity test, the optimum temperature of impregnation tank is set between in 40 and 50℃. The pre- polymer has at least 1hr pot life in order to let the fiber having enough time for processing. From the result of SEM fracture surface, and longiltudinal , the fiber have good wet-out. From above discussion, the epoxy/blocked PU have excellent process feasibility for pultrusion. From the DSC and mechanical properties tests, the optimum die temperature range is between 220℃and 240℃. From the experiment results, the range of pulling rate is set at 20 ~ 60 cm/min, and the best pulling rate is 20 cm/min. It is found that the mechanical properties increase with filler content at 3 ~ 9 phr for calcium carbonate and kaolin,respectively.The optimum postcure temperature and time is 100℃and 1.5hr.The suitable fiber glass content is between 67.3 and 74.2 wt%.
Wu, Ming-Dao, and 吳明道. "Investigating the organoclay effect on mechanical behavior of glass fiber/epoxy nanocomposites." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/01015227588716035369.
Повний текст джерела國立交通大學
機械工程系所
94
This research is aimed to investigate the organoclay effect on mechanical behaviors of the fiber/epoxy/organoclay nanocomposites. Tensile, flexure and fracture behaviors were considered in this study. To demonstrate the organoclay effect, three different loadings, 2.5, 5 and 7.5 wt% of organoclay were dispersed in the epoxy resin using mechanical mixer followed by sonication. The corresponding glass/epoxy nanocomposites were prepared by impregnating the organoclay epoxy mixture into the dry glass fiber through a vacuum hand lay-up process. For the tensile behaviors, the coupon specimens were tested in MTS machine in both longitudinal and transverse directions. The flexural properties were characterized using three point bending tests. In addition, the fracture behaviors of the fiber composites were determined from the double cantilever beam specimens. From the tensile tests, it was revealed that the longitudinal tensile strength decrease as the organoclay loading increases, on the other hand, the transverse tensile strength as well as the transverse tensile modulus increases with the increase of the organoclay. SEM observation on the transverse failure specimens indicates that the enhanced mechanism is due to the interfacial bonding between the fibers and the surrounding matrix modified by organoclay. The similar tendency was also found in the transverse flexural strength of the composites. From the mode I fracture tests It was indicated that with the increase of the organoclay, the corresponding fracture toughness of the composites decreases appreciably. In addition to the unidirectional lamina, the quasi-isotropic laminates with organoclay were prepared and tested in tension. Experimental results depict that the strength of the laminates is not affected appreciably by the organoclay.
彭運娟. "A study of vibration damping properties on glass fiber reinforced epoxy resin." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/65799715135687674279.
Повний текст джерелаPENG, CHI-HUA, and 彭基華. "A Bending Test Study for Glass Fiber/Epoxy Resins Composite Sandwich Structure." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/08964168197791242253.
Повний текст джерела中華大學
機械工程學系碩士在職專班
99
The demand for high degree of strength, corrosion-resistant, and lightweight materials has been rapidly increased in the field of aerospace, automotive and engineering. Due to their good resistance to bending, high strength, and more flexible to be redesigned, composite materials have very wide range of applications. This study focus on how the composite materials are utilized in the sandwich-structure, and to be analyzed for their performance. To construct the sandwich-structure with composite materials, glass fiber/epoxy layer are stacked up as both the top and bottom layer of the structure, while the 30k-ps high-density polystyrene foam is used as the core layer the structure. The experiment on sandwich-structure was conducted by changing several variables, such as the stacking layers of glass fiber, and the thickness of polystyrene foam in the middle layer. Furthermore, the same test was performed again with adding new variables, such as single I beam and double I beam, in order to do the comparison between those two tests. The bending tests were performed to evaluate the performance of sandwich-structure. The results indicate that, when the stacking layers of glass fiber material increase, the specimens can correspondingly withstand greater loading, bending moment, and stress. In addition, the specimens can also withstand greater loading and bending moment when the thickness of core material increases, but not the stress. It is because the same material with the same stack of layers of glass fiber can generate the same value of stress. Furthermore, the sandwich-structure with single I beam and double I beam can tolerate greater loading, bending moment and stress as well. Keywords: glass fiber, epoxy, composites, sandwich structures, bending test.
Kuo, Shu-Wei, and 郭書瑋. "Investigation on Glass Fiber Reinforced Epoxy Resin for Dry Type Transformer Insulation Application." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/86044704930301198056.
Повний текст джерела長庚大學
化工與材料工程研究所
91
High voltage transformer insulation have been designed and manufactured using glass fiber reinforced epoxy composite materials by winding techniques. This class of materials offers excellent mechanical property, high electrical insulation,good thermal stability, easy processing in design. Some structure-property relationship issues were characterized and discussed in this paper. The results show that the Tg of this material is about 120℃, the modulus is 44 GPa at room temperature, and the breakdown voltage is 32 kV in the longitudinal direction.Those property in the transverse direction is much lower than longitudinal direction.This paper deals with two different directions of composite insulation materials for HV outdoor insulation technology.The interfacial property between epoxy and fiber is the most important factor to influence its mechanical and electrical property.
楊棟賢. "A study of the impact strength of knitting fabrics of carbon fiber and glass fiber reinforced epoxy resin." Thesis, 1988. http://ndltd.ncl.edu.tw/handle/55825801485212102246.
Повний текст джерела賴其正. "A study of the fatigue strength of knitted fabrics of carbon fiber and glass fiber reinforced epoxy resin." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/20154363722327470354.
Повний текст джерелаCHUEH, CHIH-CHIEN, and 覺志堅. "Preparation and Characteristics of the Glass Fiber/SiO2–Clay–TiO2/Epoxy Resin Composite Materials." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/08970110856523808375.
Повний текст джерела逢甲大學
紡織工程所
97
In this study, we first discuss the different layers of laminations via the resistance to compression test. It was determined that the best laminations consisted of 25 layers, with thermal conduction coefficient value of 0.069 W/m℃, compressive strength of 477.65 N/mm2 and bending strength of 427.808 N/mm2. We increased the concentrations of SiO2, Clay and TiO2 by adding these three powders separately to the Glass fiber/Epoxy laminations. Then, we investigated their influence on the ratios of heat insulation, resistance to compression and bending. According to the results, thermal conduction coefficient didn’t improve significantly by adding the three kinds of powders. In the resistance to compression aspect, the compressive strength of composites increased about 15.4 % and 2.7% by adding 1 wt% of SiO2 and 3% of TiO2, respectively, and decreased about 1.5% by adding 4 wt% of Clay. In the resistance to bending test aspect, the bending strength decreased about 3.5%, 13.4% and 18% by adding 3 wt% of SiO2, 2 wt% of Clay and 3 wt% of TiO2, respectively. We used 2K factorial designs to explore and determine the selection sector that we wanted. That selection sector was used to research the effects of heat insulation, resistance to compression and bending when the three kinds of powders were added to the Glass fiber/Epoxy laminations at the same time. The research was exhibited that the most influencing factor in heat insulation aspect was the single factor. When less TiO2 and more SiO2 and Clay were added to the selection sector thermal conduction coefficient value decreased. In resistance to compression aspect, the most influencing factor was the TiO2 single factor. When less SiO2 and Clay and more TiO2 were added to the selection sector added compressive strength value increased. In resistance to bending aspect, the most influencing factor was SiO2-Clay di-factor. When less SiO2 and Clay and more TiO2 were added to the selection sector bending strength value increased.
(10725372), Rajan Nitish Jain. "Intrinsic Self-Sensing of Pulsed Laser Ablation in Carbon Nanofiber-Modified Glass Fiber/Epoxy Laminates." Thesis, 2021.
Знайти повний текст джерела吳繼仁. "A study of the mechanical properties of weaving and knitting fabrics of carbon fiber and glass fiber reinforced epoxy resin." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/02013065746321370690.
Повний текст джерелаYAN, FU-SHAN, and 顏福杉. "A study of the mechenical properties of epoxy resin composites reinforced with tridimensional glass fiber fabrics." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/88958418481738144308.
Повний текст джерела劉貴生. "A study of the effect of properties for glass fiber reinforced epoxy resin added by PCL." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/30976642529602824953.
Повний текст джерела(7026218), Akshay Jacob Thomas. "STRUCTURAL HEALTH MONITORING OF FILAMENT WOUND GLASS FIBER/EPOXY COMPOSITES WITH CARBON BLACK FILLER VIA ELECTRICAL IMPEDANCE TOMOGRAPHY." Thesis, 2019.
Знайти повний текст джерелаFiber reinforced polymer composites are widely used in manufacturing advanced light weight structures for the aerospace, automotive, and energy sectors owing to their superior stiffness and strength. With the increasing use of composites, there is an increasing need to monitor the health of these structures during their lifetime. Currently, health monitoring in filament wound composites is facilitated by embedding piezoelectrics and optical fibers in the composite during the manufacturing process. However, the incorporation of these sensing elements introduces sites of stress concentration which could lead to progressive damage accumulation. In addition to introducing weak spots in the structure, they also make the manufacturing procedure difficult.
Alternatively, nanofiller modification of the matrix imparts conductivity which can be leveraged for real time health monitoring with fewer changes to the manufacturing method. Well dispersed nanofillers act as an integrated sensing network. Damage or strain severs the well-connected nanofiller network thereby causing a local change in conductivity. The self-sensing capabilities of these modified composites can be combined with low cost, minimally invasive imaging modalities such as electrical impedance tomography (EIT) for damage detection. To date, however, EIT has exclusively been used for damage detection in planar coupons. These simple plate-like structures are not representative of real-world complex geometries. This thesis advances the state of the art in conductivity-based structural health monitoring (SHM) and nondestructive evaluation (NDE) by addressing this limitation of EIT. The current study will look into damage detection of a non-planar multiply connected domain – a filament-wound glass fiber/epoxy tube modified by carbon black (CB) filler. The results show that EIT is able to detect through holes as small as 7.94 mm in a tube with length-to-diameter ratio of 132.4 mm-to-66.2 mm (aspect ratio of 2:1). Further, the sensitivity of EIT to damage improved with decreasing tube aspect ratio. EIT was also successful in detecting sub-surface damage induced by low velocity impacts. These results indicate that EIT has much greater potential for composite SHM and NDE than prevailing work limited to planar geometries suggest.
(8803379), Ishan Tanay Karnik. "The Effect of Fatigue Loading on Electrical Impedance in Open-Hole Carbon Nanofiber-Modified Glass Fiber/Epoxy Composites." Thesis, 2020.
Знайти повний текст джерелаfatigue loading on the AC response of carbon nanofiber (CNF)-modified glass fiber/epoxy laminates. In this study, impedance magnitude and phase angle are measured along the length and through the thickness of composite specimens with an open-hole stress concentration
subjected to tension fatigue-loading up to 10 MHz. The collected impedance data is fit to an equivalent circuit model as a function of cycle. These results show that high-cycle fatigue loading does indeed have an appreciable effect on the equivalent circuit behavior of the material. However, clear and definitive trends were not observed thereby suggesting that further research is needed into the basic mechanisms of AC transport in nanocomposites if frequency-dependent transport is to be used to track fatigue loading.
Bradley, Philip. "Characterisation of the structural properties of ECNF embedded pan nanomat reinforced glass fiber hybrid composites." Thesis, 2016. http://hdl.handle.net/10539/21162.
Повний текст джерелаIn this study, hybrid multiscale epoxy composites were developed from woven glass fabrics and PAN nanofibers embedded with short ECNFs (diameters of ~200nm) produced via electrospinning. Unlike VGCNFs or CNTs which are prepared through bottom-up methods, ECNFs were produced through a top-down approach; hence, ECNFs are much more cost-effective than VGCNFs or CNTs. Impact absorption energy, tensile strength, and flexural strength of the hybrid multiscale reinforced GFRP composites were investigated. The control sample was the conventional GFRP composite prepared from the neat epoxy resin. With the increase of ECNFs fiber volume fraction up to 1.0%, the impact absorption energy, tensile strength, and flexural strength increased. The incorporation of ECNFs embedded in the PAN nanofibers resulted in improvements on impact absorption energy, tensile strength, and flexural properties (strength and modulus) of the GFPC. Compared to the PAN reinforced GRPC, the incorporation of 1.0% ECNFs resulted in the improvements of impact absorption energy by roughly 9%, tensile strength by 37% and flexural strength by 29%, respectively. Interfacial debonding of matrix from the fiber was shown to be the dominant mechanism for shear failure of composites without ECNFs. PAN/ECNFs networks acted as microcrack arresters enhancing the composites toughness through the bridging mechanism in matrix rich zones. More energy absorption of the laminate specimens subjected to shear failure was attributed to the fracture and fiber pull out of more ECNFs from the epoxy matrix. This study suggests that, the developed hybrid multiscale ECNF/PAN epoxy composite could replace conventional GRPC as low-cost and high-performance structural composites with improved out of plane as well as in plane mechanical properties. The strengthening/ toughening strategy formulated in this study indicates the feasibility of using the nano-scale reinforcements to further improve the mechanical properties of currently structured high-performance composites in the coming years. In addition, the present study will significantly stimulate the long-term development of high-strength high-toughness bulk structural nanocomposites for broad applications.
MT2016
CHEN, SHI-XIONG, and 陳世雄. "The hybrid effect of alternating interply and intermingled interply hybrid of carbon/E or S-2 glass fiber epoxy composite." Thesis, 1986. http://ndltd.ncl.edu.tw/handle/79397217584773909834.
Повний текст джерелаGemi, L., M. A. Koroglu, and Ashraf F. Ashour. "Experimental study on compressive behavior and failure analysis of composite concrete confined by glass/epoxy ±55° filament wound pipes." 2017. http://hdl.handle.net/10454/14402.
Повний текст джерелаThis paper investigates the strength and ductility of concrete confined by Glass/Epoxy ±55° Filament Wound Pipes (GFRP) under axial compression. A total of 24 cylinderical specimens were prepared with expansive and Portland cements, properly compacted and un-compacted for different composite fresh concrete matrix. Test results showed that compressive strength and axial deformation at failure of concrete confined with GFRP tubes increased by an average of 2.85 and 5.57 times these of unconfined concrete, respectively. Macro and micro analyses of GFRP pipes after failure were also investigated. Debonding, whitening, matrix/transfer cracking, delamination and splitting mechanisms were detected at failure, respectively. The experimental results were also employed to assess the reliability of design models available in the literature for confined concrete compressive strength.
江健瑋. "Synergistic Effects of Mechanical Properties on Graphene Nanoplatelet/Multi-walled carbon nanotube Hybrid Reinforced Epoxy/Glass Fiber Composite Laminates via VARTM Process." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/gaz7w5.
Повний текст джерела中華科技大學
飛機系統工程研究所
107
In this study, the synergistic effect on mechanical properties of graphene nanoplatelets (GNPs)/multi-walled carbon nanotube (MWCNTs) reinforced epoxy/glass fiber composite (GFRP) laminates via VARTM process were investigated. The mechanical properties of MWCNTs reinforced GFRP laminate were investigate in the preliminary study in order to understand the reinforce behavior of single carbon nanomaterials reinforced GFRP. After discuss the above experiment result, the GNP/CNT hybrids (0.1, 0.25, 0.5 and 1.0 wt%) with different mixing ratios (i.e., 9:1, 5:5, and 1:9) were dispersed in epoxy resin to prepare GNP/CNT/GFRP laminates. The mechanical properties such as ultimate tensile strength, flexural strength, flexural modulus, and interlaminar shear strength (ILSS) of these nanocomposite laminates were investigated. Additionally, the fracture surfaces of the specimens examined using field-emission scanning electron microscopy to determine the dispersal mechanisms and reinforce behavior of the GNP/CNT hybrids in the GFRP laminate. The experimental results indicate that the mechanical properties of GNP/CNT/GFRP laminates are optimized by reinforcement through the addition of GNP/CNT hybrids. A synergistic effect was noticed when the GNP/CNT hybrids were added. The mechanical properties of the GNP/CNT/GFRP laminates, such as the tensile strength, flexural strength, and ILSS, were superior to those of the GFRP laminate containing a single carbon nanomaterial and neat GFRP laminate. However, the Young’s modulus and flexural modulus of the GNP/CNT/GFRP laminate show negligible improvements compared to that of the n containing a single carbon nanomaterial and neat GFRP laminate.
Xu, Joana. "Estudo de compósitos estruturais no processo de produção de pás eólicas." Master's thesis, 2019. http://hdl.handle.net/10316/93551.
Повний текст джерелаO tema da presente dissertação, “Estudo de compósitos estruturais no processo de produção de pás eólicas”, decorreu em ambiente industrial através da colaboração institucional da Ria Blades, SA, Vagos, Aveiro. A grande competitividade e a concorrência dos mercados incentivam as empresas à adaptação de novos desafios, promovendo uma constante evolução para serem bem sucedidas.Os objetivos gerais propostos para este trabalho consistiram na i) otimização do processo de produção de laminados de reforços de acabamento a aplicar na linha de colagem de uma pá eólica e ii) a sua implementação na linha de produção.Para tal, foram utilizadas várias abordagens, destacando-se diferentes processos de impregnação das fibras (manual e mecânica), compactação a vácuo com folhas poliméricas distintas e ainda o uso ou não de uma intercamada designada por folha desmoldante.Os resultados obtidos permitem concluir, genericamente, que a impregnação mecânica conduz a uma poupança de resina epoxídica e a uma molhabilidade mais uniforme do laminado. Na moldação a vácuo, a utilização de sacos à base de nylon compactam melhor que os de polietileno, tendo-se obtido valores de espessura e de porosidade menores no compósito final. A presença ou não da camada de folha desmoldante parece não afetar o processo de produção.Face a esses resultados, para otimizar a linha de produção, a empresa irá manter o saco de vácuo à base de nylon na linha de produção e será retirada a camada de folha desmoldante, sendo a impregnação das fibras feita mecanicamente.
The theme of this dissertation, "Study of structural composites in the wind turbine production process", was carried out in an industrial environment through the institutional collaboration of the Ria Blades, SA, Vagos, Aveiro. The high market competitiveness and the rivalry in the business sector, encourages the companies to adapt to new challenges and constantly evolve to survive to be successful.The general objectives proposed for this work were: i) optimization of the production process of finishing reinforcement laminates to be applied in the glue line of a wind blade and ii) its implementation in the production line.For this, several approaches were used, highlighting different processes of fiber impregnation (manual and mechanical), vacuum compaction by using different polymer sheets and the use or not of an interlayer called release sheet.The experimental results obtained, allow concluding that the mechanical impregnation of the glass fibers by epoxy resin is a both economical and efficient process. In vacuum molding, it appears that the nylon bag compacts better than the polyethylene one, resulting in lower values of thickness and porosity in the composite. The presence or not of the release film layer does not appear to affect the process as a whole.Faced with these results, the company will keep the vacuum nylon-based bag and discharge the release-foil layer to optimize the production line of the wind turbine blade, with the impregnation of the fibers done mechanically.
Jorge, Rafael dos Santos. "Análise do estado de deformação em laminados vidro/epóxido imersos em água salgada sujeitos a cargas cíclicas." Master's thesis, 2021. http://hdl.handle.net/10316/98234.
Повний текст джерелаO uso de materiais compósitos em todas as áreas de desenvolvimento tem sido cada vez mais abundante devido à robustez e às características variadas que se podem obter através da mistura de diferentes tipos de materiais.A indústria naval é um grande setor no qual a utilização de materiais compósitos prevalece sobre outros tipos de materiais, pelo que é natural desenvolver estudos e investigações em materiais para este setor em específico. Neste setor os compósitos são sujeitos a solicitações agressivas em simultâneo com a inserção num ambiente corrosivo.Esta dissertação tem como objetivo principal entender o efeito de um ambiente salino em compósitos de epóxi reforçado com fibras de vidro, bem como os efeitos que o pré-carregamento pode ter na vida à fadiga de um provete deste tipo de compósito.Foram ensaiados 16 provetes do material compósito referido no parágrafo anterior cuja imersão em ambiente salino durou 900 dias, observando-se após este período uma percentagem de absorção de água de cerca de 1% do peso do provete. Destes, 9 provetes foram pré-carregados em grupos de 3, com 25%, 50% e 75% de pré-carga.Aquando da solicitação à fadiga, os provetes foram fotografados com duas câmaras calibradas para posterior análise com o programa de correlação de imagem digital VIC3D®. Após obtenção dos valores de deformação principal e sobre o eixo y (direção de solicitação), estes foram analisados graficamente com o programa Microsoft Excel®.Com o aumento do teor de água no provete há a perda de resistência à fadiga do mesmo, como é comprovado na curva S-N: a curva dos provetes imersos durante 900 dias no ambiente salino apresentam piores resultados do que as curvas S-N dos provetes de controlo e do que os provetes imersos durante 229 dias, o que confirma a redução de resistência à fadiga do provete com a exposição a ambientes corrosivos salinos.Relativamente à perda de resistência do provete causada pelo pré-carregamento, não se obtiveram resultados totalmente conclusivos, uma vez que não há uma linearidade entre o valor da pré-carga e o número de ciclos completos pelo provete.
The use of composite materials has been more abundant due to its robustness and to the variety of characteristics that can result from the mixture of different types of materials.The naval industry is a major sector in wich composite materials play a significant role. This motivates the investigation and development of composites for this sector specifically. In this type of industry the materials are subject to various forces while being in contact with a corrosive environment.This dissertation has the objective of understanding the effect of a seawater environment in glassfiber reinforced epoxi composites, as well as the effects that a pre-load can have on the fatigue life of this type of composite.16 specimens were immersed in saltwater for 900 days, a period after wich the mass of the specimens had increased by 1% of its weight due to water infiltration. From these, 9 of specimens were pre-loaded in groups of 3, with the loads being 25%, 50% and 75%.While under fatigue testing, the specimens were photographed using two calibrated cameras paired with the digital image correlation program VIC3D®. After extracting the principal strain and the y axis strain values, these were graphically analysed using Microsoft Excel®.With the rise of water contente in the specimen, there is a loss of properties of fatigue resistance, wich is proved with S-N curve values: the 900 days immersed specimens showed worse results than the 229 days immersed specimens and the control specimens, wich confirms the reduction of fatigue resistance due to corrosive saltwater environments.The loss of fatigue resistance due to pre-load is not fully conclusive because the results of the testing are not linear between the pre-load and the number of cycles complete.
Goldmann, Joseph. "Schädigungsprognose mittels Homogenisierung und mikromechanischer Materialcharakterisierung." Doctoral thesis, 2017. https://tud.qucosa.de/id/qucosa%3A31075.
Повний текст джерелаThe thesis at hand is concerned with the question if numerical homogenization schemes can be of use in deriving effective material properties of composite materials after the onset of strain localization due to strain softening. In this case, the usefulness of computational homogenization methods has been questioned in the literature. Hence, all the subtasks to be solved in order to provide a successful homogenization scheme are investigated herein. The first of those tasks is the characterization of the constituents, which form the composite. To allow for an experimentally based characterization an exemplary composite has to be chosen, which herein is a glass fiber reinforced epoxy. Hence the constituents to be characterized are the epoxy and the glass fibers. Furthermore, special attention is paid to the characterization of the interface between both materials. In case of the glass fibers, the measured strength values do not comply with the weakest link hypothesis. Numerous generalizations of the Weibull distribution are investigated, to account for interfering effects. Finally, distributions are derived, that incorporate the possibility of failure inside the clamped fiber length. Application of such a distribution may represent the measured data quite well. Additionally, it renders the cumbersome process of sorting out and repeating those tests unnecessary, where the fiber fails inside the clamps. Identifying the interface parameters of the proposed cohesive zone model relies on data from pullout and single fiber fragmentation tests. The agreement of both experiments in terms of interface strength and energy release rate is very good, where the parameters are identified by means of an evaluation based on finite element models. Also, the agreement achieved is much better than the one typically reached by an evaluation based on simplified analytical models. Beside the derivation of parameterized material models as an input, the homogenization scheme itself needs to be generalized after the onset of strain localization. In an assessment of the current state of the literature, prior to the generation of representative volume elements and the averaging operator, the boundary conditions (BC) are identified as a significant issue of such a homogenization scheme. Hence, periodic BC, linear displacement BC and minimal kinematic BC as well as two adaptive BC, namely percolation path aligned BC and generalized periodic BC are investigated. Furthermore, a third type of adaptive BC is proposed, which is called tesselation BC. Firstly, the three adaptive BC are proven to fulfill the Hill-Mandel condition. Secondly, by modifying the Hough transformation an unbiased criterion to determine the direction of the localization zone is given, which is necessary for adaptive BC. Thirdly, the properties of all the BC are demonstrated in several examples. These show that tesselation BC are the only type, that allows for arbitrary directions of localization zones, yet is totally unsusceptible to spurious localization zones in corners of representative volume elements. Altogether, fundamental objections, that have been raised in the literature against the application of homogenization in situations with strain localization, are rebutted in this thesis. Hence, the basic feasibility of homogenization schemes even in case of strain softening material behavior is shown.
Vijaya, Kumar R. L. "Some Experimental and Numerical Studies on Evaluation of Adhesive Bond Integrity of Composites Lap Shear Joints." Thesis, 2014. http://hdl.handle.net/2005/3220.
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