Dissertations / Theses on the topic 'Epoxy Glass Fiber'
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1
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.
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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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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.
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Bilyeu, 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/.
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Kinetic equation parameters for the curing reaction of a commercial glass fiber reinforced high performance epoxy prepreg composed of the tetrafunctional epoxy tetraglycidyl 4,4-diaminodiphenyl methane (TGDDM), the tetrafunctional amine curing agent 4,4'-diaminodiphenylsulfone (DDS) and an ionic initiator/accelerator, are determined by various thermal analysis techniques and the results compared. The reaction is monitored by heat generated determined by differential scanning calorimetry (DSC) and by high speed DSC when the reaction rate is high. The changes in physical properties indicating increasing conversion are followed by shifts in glass transition temperature determined by DSC, temperature-modulated DSC (TMDSC), step scan DSC and high speed DSC, thermomechanical (TMA) and dynamic mechanical (DMA) analysis and thermally stimulated depolarization (TSD). Changes in viscosity, also indicative of degree of conversion, are monitored by DMA. Thermal stability as a function of degree of cure is monitored by thermogravimetric analysis (TGA). The parameters of the general kinetic equations, including activation energy and rate constant, are explained and used to compare results of various techniques. The utilities of the kinetic descriptions are demonstrated in the construction of a useful time-temperature-transformation (TTT) diagram and a continuous heating transformation (CHT) diagram for rapid determination of processing parameters in the processing of prepregs. Shrinkage due to both resin consolidation and fiber rearrangement is measured as the linear expansion of the piston on a quartz dilatometry cell using TMA. The shrinkage of prepregs was determined to depend on the curing temperature, pressure applied and the fiber orientation. Chemical modification of an epoxy was done by mixing a fluorinated aromatic amine (aniline) with a standard aliphatic amine as a curing agent for a commercial Diglycidylether of Bisphenol-A (DGEBA) epoxy. The resulting cured network was tested for wear resistance using tribological techniques. Of the six anilines, 3-fluoroaniline and 4-fluoroaniline were determined to have lower wear than the unmodified epoxy, while the others showed much higher wear rates.
5
Bozkurt, 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.
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Thesis (Master)--İzmir Institute of Technology, İzmir, 2006Keywords: polymer composites, Nanoparticles, glass fiber, mechanical properties, thermal properties. Includes bibliographical references (leaves 75-79).
6
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.
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The 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.
7
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.
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Al-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.
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This thesis includes the study of the mechanical performance of two different types of fibers reinforced hybrid composites. Two kinds of fibers, natural fiber (flax) and synthetic fiber (E-glass), are used to reinforce epoxy resin. To evaluate the effective properties of the hybrid composites, a micromechanical analysis of the structure genome (SG) of a unidirectional fiber hybrid composites is performed using nite element analysis (FEA). Both fibers are assumed to be circular and packed in a hexagonal pattern. The effects of varying volume fractions and fiber locations, of the two fibers, on the elastic properties of the hybrid composites are studied using FEA. Rule of hybrid mixtures (RoHM) and Halpin-Tsai equations, which are analytical equations, are used as a preliminary prediction of the elastic constants of the hybrid composites. Then, the comparison is made between FEA and analytical results. The predicted elastic constants through numerical homogenization are in good a agreement with analytical results. The effect of changing fiber locations on the tensile strength of hybrid composite is investigated using tensile tests. Impact strength of single fiber composites and ax/glass fiber hybrid composites, in which various stacking sequences of ax and glass fibers are used, are obtained using Charpy impact tests. Moisture absorption test was performed by immersing single fiber composites and various stacking sequences of hybrid composites in deionized water at room temperature for a week. To investigate the effect of water absorption on the tensile properties of composite, tensile test was done on various stacking sequences of the hybrid composite. FEA and analytical equations showed that Young's and shear moduli increased and the axial Poison's ratio decreased linearly with the glass fiber content. Also, FEA showed that changing fiber locations have no effect on the effective properties of the hybrid composite. However, changing fiber stacking sequences showed a significant effect on tensile strength, impact strength, and water absorption properties of the hybrid composites. It was concluded that better design of the hybrid composite was achieved when glass fibers placed on the extreme positions and flax fibers in the middle. Positive hybrid effect is achieved from hybridization of E-glass fiber with flax fiber.
9
Papangelou, Christopher G. "Material Properties and Volumetric Porosity of Biomaterials for Use in Hard Tissue Replacement." Scholar Commons, 2005. https://scholarcommons.usf.edu/etd/808.
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Metal implants are a type of hard tissue replacement currently used. Metals used for implants include: stainless steel, titanium, chrome, and cobalt alloys. Such implants often fail at the interface with bone. Metal implants fail when the surface of the implant is coated with an osteoconductive material. An osteoconductive material provides scaffolding for cellular migration, cellular attachment, and cellular distribution. A reason for metal implant failure could be the vastly different material properties than bone. Motivation for the research was to find a suitable bone substitute other than metal. Materials considered were: zirconia toughened alumina, carbon fiber reinforced epoxy, and glass fiber reinforced epoxy. Those materials have been used in previous biological applications and can be cast into complex configurations.
Objectives of the study were to compare material properties of the composites to bone. A method to create porosity was then tested in the material that was similar to bone in critical material property.
Some of the materials were statistically similar to bone in yield strength. Method to create interconnected porosity in those materials resulted in 49% void space.
10
Embley, 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.
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Compression strength after impact tests were conducted on unidirectional composite rods with sleeves. These elements represent local members of open three-dimensional composite lattice structures (e.g., based on isogrid or IsoTruss® technologies). The unidirectional cores composed of carbon, glass, or basalt fiber/epoxy composites were co-cured in aramid sleeves. Sleeve patterns included both bi-directional (unsymmetric) braids and unidirectional spiral wraps with sleeve coverage ranging from nominally half to full. The diameters were nominally 8 and 11 mm (5/16 and 7/16 in). The larger diameter had nominally twice the cross-sectional area, to quantify the effects of scaling. The specimens were long enough to encourage local buckling failure as expected in members of typical composite lattice structures. The unsupported lengths varied from 127 mm (5.0 in) to 160 mm (6.3 in). Specimens were radially impacted at mid-length with energy levels ranging from 0 to 20 J (0 to 14.8 ft-lbs) and tested in longitudinal compression to quantify the effects of local impact damage on the buckling strength. In undamaged specimens, sleeve type and sleeve coverage have no effect on the ultimate compression strength of carbon, glass, or basalt composites (7% or less standard deviation for each material). When impacted, the influence of sleeve type and sleeve coverage varies with the type of fiber in the unidirectional core. Sleeve type and coverage did not affect the compression strength after impact for fiberglass composites. On the other hand, both carbon and basalt composites exhibited improved performance with braided (vs. spiral) sleeves (up to 34% stronger) and full (vs. half) coverage (up to 38% stronger). The compression strength of carbon configurations decreases with increasing impact energy regardless of sleeve type or coverage. The higher flexibility of glass and basalt composites, however, allowed some configurations to maintain the same compression strength after impact as their undamaged counterparts, at lower impact energy levels. Doubling cross-sectional area of basalt composites significantly improves the stiffness and compression strength after impact, more than doubling the impact energy required to achieve the same compression strength.
11
Dhillon, Jagminder. "Coated fibre composites using rubbery and ductile fibre/matrix interlayers." Thesis, Loughborough University, 1991. https://dspace.lboro.ac.uk/2134/33043.
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Advanced composite materials possessing high specific stiffness and strength have been successfully employed as structural materials in the aerospace, military and automotive industries. Despite the advantages that composites have over other materials, further development has been restricted by their brittleness. The aim of this research project was to improve the energy absorbing capabilities of unidirectional glass fibre epoxy resin composites by coating the fibres with an interlayer. UHMWPE was used as the interlayer because of its outstanding toughness while EPDM of low modulus was used to assess the difference between energy absorption through plastic deformations (UHMWPE) and highly elastic deformations (EPDM).
12
Subagio, 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.
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Essais d'identification d'une loi locale d'endommagement de fatigue basée sur la théorie de Kachanov-Rabotnov à partir d'essais mécaniques. Intégration de cette loi dans un calcul de structure. Introduction de la notion de dispersion par l'application d'une loi de Weibull. Identification de la dispersion locale à partir de la dispersion globale par la méthode de simulation de Monte-Carlo.
13
Nesa, Daniel. "Etude de la fissuration d'un composite unidirectionnel verre-résine." Paris, ENMP, 1987. http://www.theses.fr/1987ENMP0093.
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Coignac, 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.
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Kretsis, George. "Mechanical characterisation of hybrid glass/carbon fibre-reinforced plastics." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46982.
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Berg, Jolyon. "The role of fibre coatings on interphase formation in glass fibre epoxy resin composites." Thesis, University of Sheffield, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245546.
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Masse, Bruno. "Analysis of structural timber joints made with glass fibre/epoxy." Thesis, Coventry University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273732.
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Aasrum, Pål Einar. "A numerical and experimental investigation of glass fibre reinforced epoxy pipes /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0016/MQ55014.pdf.
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Taniguchi, Shinro. "Measurement of the through-thickness strength of composites." Thesis, University of Oxford, 1998. http://ora.ox.ac.uk/objects/uuid:441ed7e2-72ed-4c2e-b0d2-066b5419b56e.
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This research deals with the mechanical characterisation of thick composite laminates in the through-thickness direction. Three independent glass fibre/epoxy laminate configurations, namely cross, quasi-isotropic, and woven, plies were investigated. Six specimen configurations, of which two were developed herein, were employed in order to determine the strength behaviour of these three laminate configurations when subjected to interlaminar shear and interlaminar tensile stresses in isolation and in combination. The stress and strain distributions were estimated using the ABAQUS FEA package. The strain distribution obtained thereby was verified experimentally via Moirandeacute; interferometry which records the exact strain field at the test section. A two dimensional failure envelope is defined for each laminate configuration using the experimentally obtained data. All three independent laminate configurations exhibited almost identical failure envelopes. The woven laminate exhibited superior interlaminar shear strength when subjected to combined interlaminar shear and interlaminar tensile stresses, whereas the cross-ply laminate exhibited superior interlaminar tensile strength when subjected to the same combination of stress. The characteristics of the quasi-isotropic laminate were similar to that of the cross-ply laminate. A partial three dimensional failure envelope was also defined for the materials tested.
20
Nensi, Tahera. "A study of stress-induced whitening in glass fibre reinforced epoxy laminates." Thesis, University of Surrey, 1988. http://epubs.surrey.ac.uk/844140/.
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The aim of this study has been to investigate stress-induced whitening in glass fibre/epoxy (0,90)s laminates and to develop a technique to monitor the low strain damage associated with it. The effect of resin cure, laminate geometry, heat treatment and surface finish of glass fibres on the extent and development of damage has also been studied. It has been found that the whitening is caused by the development of micro-cracks in the resin. The micro-cracks developed in the 90° ply and occurred predominantly at or near points of contact between fibres where the strain magnification in the resin is highest. The cracks occurred near the fibre/matrix interface and extended into the resin with the crack faces lying at 90° to the loading axis. Careful observation under oblique illumination conditions has shown that the whitening effect is preceded by other colour effects so that the laminate is observed to gradually change colour from an original blue through to red or white depending on the level of cure of the matrix resin. The whitening is a result of ordinary diffuse reflections from cracks that are larger than the wavelength of light and occurs when the level of cure of the matrix system is low while the reddening is the result of Rayleigh or Mie scattering from cracks that are smaller than the wavelength of light and occurs when the level of cure of the matrix is high. An off-axis LASER diffraction technique has been developed to monitor the amount of damage in the transverse ply of laminates by measurement of the intensity of light diffracted by the micro-cracks. In addition to confirming the results obtained from photomicroscopy, it revealed that decreasing the inner 90° ply thickness in (0,90)s laminates resulted in a substantial increase in the amount of micro damage in the laminate. Heat treatment of the laminate after testing resulted in the disappearance of whitening and healing of micro-cracks in the resin which continues to cure during heat treatment. Successive heat treatments reduced the size of micro-cracks which developed on reloading. In addition to decreasing the rate of re-development of the original cracks on reloading, the heat treatment reduced the rate of development of "new" cracks formed at higher applied strains.
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Gao, Xiao. "Tailored interphase structure for improved strength and energy absorption of composites." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 5.63 Mb., 321 p, 2006. http://proquest.umi.com/pqdlink?did=1172119431&Fmt=7&clientId=79356&RQT=309&VName=PQD.
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Amico, Sandro Campos. "Permeability and capillary pressure in the infiltration of fibrous porous media in resin transfer moulding." Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/1011/.
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Prickett, Andrew C. "Intralaminar cracking of fibre reinforced composites : a fracture mechanics and ToF-SIMS study." Thesis, University of Surrey, 2001. http://epubs.surrey.ac.uk/798035/.
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Martens, Michael G. "Biaxial monotonic and fatigue behaviour of a multidirectional glass fibre-reinforced epoxy pipe." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ40086.pdf.
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Demirer, Halil. "Glass fibre coatings based on polyimide-silica hybrids for use in epoxy matrix composites." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/33046.
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Despite the advantages that composites have over monolithic materials, their use has been restricted by some deficiencies in their properties. The goal of this study was to overcome deficiencies of unidirectional glass fibre epoxy resin composites by coating the fibres with a "tailored" interlayer. Polyimide–silica hybrids, also known as ceramers, based on hydrolysed tetraethoxysilane and a polyamic acid solution mixture were used to coat glass fibres for epoxy composites. The silica part of these hybrids appears to be present either as dispersed discrete particles or as continuous nano-sized domains trapped within the polyimide matrix. The structure of hybrids determines the final properties. In this study both types of morphologies for the interlayers were utilised to obtain different mechanical, thermal and thermomechanical properties.
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Wormann, Thomas Verfasser], Martin [Akademischer Betreuer] Möller, and Andrij Z. [Akademischer Betreuer] [Pich. "Interphase modification and characterisation in p-aramid/ glass fibre epoxy model composites / Thomas Wormann ; Martin Möller, Andrij Pich." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1130326748/34.
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Wormann, Thomas [Verfasser], Martin [Akademischer Betreuer] Möller, and Andrij Z. [Akademischer Betreuer] Pich. "Interphase modification and characterisation in p-aramid/ glass fibre epoxy model composites / Thomas Wormann ; Martin Möller, Andrij Pich." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://nbn-resolving.de/urn:nbn:de:hbz:82-rwth-2016-019749.
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Wormann, Thomas [Verfasser], Martin Akademischer Betreuer] Möller, and Andrij Z. [Akademischer Betreuer] [Pich. "Interphase modification and characterisation in p-aramid/ glass fibre epoxy model composites / Thomas Wormann ; Martin Möller, Andrij Pich." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1130326748/34.
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Galvão, José Rodolfo. "Sensor a fibra ótica encapsulado em resina polimérica com reforço de fibra de vidro para aplicação em gerador de alta potência." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1299.
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ANEEL; FINEP; CAPES; CNPQ; Fundação AraucáriaNeste trabalho é apresentada uma aplicação de sensores à fibra ótica baseados em redes de Bragg encapsulados em compósito de resina polimérica com reforço de fibra de vidro. Foram avaliadas três resinas epóxi comerciais. O objetivo do trabalho é caracterizar os compósitos e investigar a viabilidade de embeber sensores a fibra ótica, baseados em redes de Bragg em fibras óticas em compósito epóxi. Na caracterização das amostras, foram realizados: Ensaios para avaliar a tensão residual após a cura das amostras. Nos ensaios, foram utilizados sensores FBGs incrustados no compósito. Ensaios para avaliar a temperatura de transição vítrea através da técnica Calorimetria Exploratória Diferencial (DSC). Ensaios de tração axial e flexão simples utilizando máquina de teste universal e ensaios para avaliar o comportamento do compósito quando sujeito a uma carga fixa e temperatura variando de 20 °C até a temperatura limite da transição vítrea do compósito. Os resultados mostram um elevado grau de integração das FBGs no compósito epóxi. Um dos resultados é promissor para aplicações em um gerador de alta potência e em ambientes hostis com temperatura de trabalho até 127 °C.
This work presents an application of optical fiber sensors based on Bragg gratings encapsulated in polymeric composite resin with glass fiber reinforcement. Three commercial epoxy resins were evaluated. The main objective of the study is to characterize the composites and investigate the feasibility of embedding the optical fiber sensors based on Bragg gratings in epoxy composite. In the characterization of the samples tensile tests were performed to evaluate the residual stress after the curing process. The residual stress was investigated by mains of a FBG sensor embedded in the composite. Additionally, tests were conducted to evaluate the glass transition temperature by DSC technique. The values of the axial tensile and simple flexural stress were investigated using a universal testing machine. In addition, tests were performed for evaluating the composite behavior when subjected to a fixed load and variable temperature ranging from 20 °C to the temperature limit of the glass transition of the composite. The results show a high level of integration of the FBGs with the epoxy composite. One of the results is promising for applications in a high power generator and in hostile environments working at temperatures up to 127 °C.
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Turmel, J.-P. "Effect of phase separation in Epoxy/PEI matrix on the mixed - mode I/II delamination behaviour of unidirectional glass fibre reinforced composites." Thesis, Cranfield University, 1995. http://dspace.lib.cranfield.ac.uk/handle/1826/11335.
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The study reported in this thesis investigates the relationships between the
morphology of PEI/epoxy blends reinforced with glass fibres and their fracture
properties.
Hot stage optical microscopy is used to study the phenomenon of phase
separation in the thermosetting blends in the presence of glass, carbon and
aramid fibres. Phase separation is shown to be unaffected by the presence of
aramid and carbon fibres, but is affected by the presence of glass fibres, to a
degree which mainly depends on the PEI concentration. Other parameters like
cure temperature, the nature of the glass fibre surface and fibre volume fraction
are also examined. The most striking feature is the initiation and development
of an epoxy-rich layer around the fibres for blends modified with 15 wt % PEI.
This concentration corresponds to a co-continuous network of PEI-rich particles
embedded in an epoxy-rich matrix.
The effects of morphologies formed during phase separation on the
fracture properties of glass fibre-reinforced composites are studied using the
mixed-mode bending test rig developed by NASA. Extensive scanning electron
microscopy (SEM) observations provide qualitative support to the delamination
results. They show that different micro-mechanisms of deformation can occur,
depending on the matrix microstructure and the fibre/matrix interfacial strength.
SEM observations show that cusps are not only present under mode II
loading, but also under mixed-mode I/II loading. They reveal that the spatial
density and angle of cusps depend on the applied loading mode, the interfacial
strength and the nature of the matrix itself. These observations are the base of
a model which describes the delamination behaviour of composites from pure
mode Ito pure mode II loading.
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Turmel, Denis Jean-Pierre. "Effect of phase separation in epoxy/PEI matrix on the mixed-mode I/II delamination behaviour of unidirectional glass fibre reinforced composites." Thesis, Cranfield University, 1995. http://dspace.lib.cranfield.ac.uk/handle/1826/11335.
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The study reported in this thesis investigates the relationships between the morphology of PEI/epoxy blends reinforced with glass fibres and their fracture properties. Hot stage optical microscopy is used to study the phenomenon of phase separation in the thermosetting blends in the presence of glass, carbon and aramid fibres. Phase separation is shown to be unaffected by the presence of aramid and carbon fibres, but is affected by the presence of glass fibres, to a degree which mainly depends on the PEI concentration. Other parameters like cure temperature, the nature of the glass fibre surface and fibre volume fraction are also examined. The most striking feature is the initiation and development of an epoxy-rich layer around the fibres for blends modified with 15 wt % PEI. This concentration corresponds to a co-continuous network of PEI-rich particles embedded in an epoxy-rich matrix. The effects of morphologies formed during phase separation on the fracture properties of glass fibre-reinforced composites are studied using the mixed-mode bending test rig developed by NASA. Extensive scanning electron microscopy (SEM) observations provide qualitative support to the delamination results. They show that different micro-mechanisms of deformation can occur, depending on the matrix microstructure and the fibre/matrix interfacial strength. SEM observations show that cusps are not only present under mode II loading, but also under mixed-mode I/II loading. They reveal that the spatial density and angle of cusps depend on the applied loading mode, the interfacial strength and the nature of the matrix itself. These observations are the base of a model which describes the delamination behaviour of composites from pure mode Ito pure mode II loading.
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Cormier, Daniel. "Repair of Conductive Layer on Carbon Fibre Reinforced Polymer Composite with Cold Gas Dynamic Spray." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33160.
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Carbon fibre reinforced composites are known for their high specific strength-to-weight ratio and are of great interest to the aerospace industry. Incorporating these materials into the fuselage, like in Boeing's 787 "Dreamliner", offers considerable weight reduction which increases flying efficiency, and reduces the cost of flying.
In flight, aircraft are often subject to lightning strikes which, in the case of composites, can result in localized melting given the high resistive nature of the material. Aerospace carbon fibre composites often incorporate a metallic mesh or foil within the composite layers to dissipate the electrical charge through the large aircraft. The damage to the aircraft is minimized but not always eliminated. This research aims to elaborate a practical technique to deposit thin layers of conductive material on the surface of aerospace grade composites. Using Cold Gas Dynamic Spray (CGDS), such coatings could be used to repair damaged components.
An experimental research approach was used to develop metallic coated composites. Using the CGDS equipment of Centerline (SST-P), specific parameters (such as gas temperature and stagnation pressure) were determined for each type of metallic coating (tin-based & copper-based). The use of bond coats was explored in order to attain the desired coatings. Once optimized, these coatings were evaluated with respect to their corrosive, adhesive, and electrical properties following industry standards.
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Akgul, Eralp. "Effects Of Mold Temperature And Vacuum In Resin Transfer Molding." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607952/index.pdf.
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The purpose of this study was to investigate the effects of mold temperature, initial resin temperature, and the vacuum, applied at resin exit ports, on the mechanical properties of epoxy matrix woven glasss fiber reinforced composite specimens produced by Resin Transfer Molding (RTM).
For this purpose, six different mold temperatures (25º, 40º
, 60º
, 80º
, 100º
, and 120º
C), two initial resin temperatures (15º
and 28º
C), and vacuum (0.03 bar) and without vacuum (~1 bar) conditions were used. Specimens were characterized by using ultrasonic (C-Scan) inspection, mechanical tests (Tensile, Flexural, Impact), thermal analyses (Ignition Loss, TGA) and scanning electron microscopy (SEM). It was generally observed that mechanical properties of the specimens produced with a mold temperature of 60º
C were the best (e.g. 16%, 43%, and 26% higher tensile strength, Charpy impact toughness and flexural strength values, respectively). When vacuum was not applied, the percentage of &ldquo
voids&rdquo
increased leading to a decrease in mechanical properties such as 26% in Charpy impact toughness and 5% in tensile and flexural strength. Lower initial resin temperature also decreased mechanical properties (e.g. 14% in tensile strenght and 18% in Charpy impact toughness).
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Humphreys, Matthew. "Development and structural investigation of monocoque fibre composite trusses." Thesis, Queensland University of Technology, 2003. https://eprints.qut.edu.au/15898/1/Matthew_Humphreys_Thesis.pdf.
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Fibre composite materials are gaining recognition in civil engineering applications as a viable alternative to traditional materials. Their migration from customary automotive, marine, aerospace and military industries into civil engineering has continued to gain momentum over the last three decades as new civil engineering applications develop. The use of fibre composite materials in civil engineering has now evolved from non-structural applications, such as handrails and cladding, into primary structural applications such as building frames, bridge decks and concrete reinforcement. However, there are issues which are slowing the use of fibre composite materials into civil engineering. Issues include high costs, difficulties in realising potential benefits, general lack of civil engineers' familiarity with the material and relatively little standardisation in the composites industry. For composites to truly offer a viable alternative to traditional construction materials in the civil engineering marketplace, it is essential that these issues be addressed. It is proposed that this situation could be improved by demonstrating that potential benefits offered by composites can be achieved with familiar civil engineering forms. These forms must be well suited to fibre composite materials and be able to produce safe and predictable civil engineering structures with existing structural engineering methods. Of the numerous structural forms currently being investigated for civil engineering applications, the truss form appears particularly well suited to fibre composites. The truss is a familiar structural engineering form which possesses certain characteristics that make it well suited to fibre composite materials. In this research a novel monocoque fibre composite truss concept was developed into a working structure and investigated using analytical and experimental methods. To the best of the author's knowledge the research presented in this thesis represents the first doctoral research into a structure of this type. This thesis therefore presents the details of the development of the monocoque fibre composite (MFC) truss concept into a working structure. The developed MFC truss was used as the basis for a detailed investigation of the structural behaviour of the MFC truss elements and the truss as a whole. The static structural behaviour of the principal MFC truss elements (tension members, compression members and joints) was investigated experimentally and analytically. Physical testing required the design and fabrication of a number of novel test rigs. Well established engineering principles were used along with complex finite element models to predict the behaviour of the tested truss elements and trusses. Results of the theoretical analysis were compared with experimental results to determine how accurately their static structural behaviour could be predicted. It was found that the static structural behaviour of all three principal truss elements could be accurately predicted with existing engineering methods and finite element analysis. The knowledge gained from the investigation of the principal truss elements was then used in an investigation of the structural behaviour of the MFC truss. Three full-scale MFC trusses were fabricated in the form of conventional Pratt, Howe and Warren trusses and tested to destruction. The investigation included detailed finite element modelling of the full-scale trusses and the results were compared to the full-scale test results. Results of the investigation demonstrated that the familiar Pratt, Howe and Warren truss forms could be successfully manufactured with locally available fibre composite materials and existing manufacturing technology. The static structural behaviour of these fibre composite truss forms was accurately predicted with well established engineering principles and finite element analysis. A successful marriage between fibre composite materials and a civil engineering structure has been achieved. Monocoque fibre composite trusses have been developed in the familiar Pratt, Howe and Warren truss forms. These structures possess characteristics that make them well suited to applications as primary load bearing structures.
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Humphreys, Matthew. "Development and Structural Investigation of Monocoque Fibre Composite Trusses." Queensland University of Technology, 2003. http://eprints.qut.edu.au/15898/.
Full textAbstract:
Fibre composite materials are gaining recognition in civil engineering applications as a viable alternative to traditional materials. Their migration from customary automotive, marine, aerospace and military industries into civil engineering has continued to gain momentum over the last three decades as new civil engineering applications develop. The use of fibre composite materials in civil engineering has now evolved from non-structural applications, such as handrails and cladding, into primary structural applications such as building frames, bridge decks and concrete reinforcement. However, there are issues which are slowing the use of fibre composite materials into civil engineering. Issues include high costs, difficulties in realising potential benefits, general lack of civil engineers' familiarity with the material and relatively little standardisation in the composites industry. For composites to truly offer a viable alternative to traditional construction materials in the civil engineering marketplace, it is essential that these issues be addressed. It is proposed that this situation could be improved by demonstrating that potential benefits offered by composites can be achieved with familiar civil engineering forms. These forms must be well suited to fibre composite materials and be able to produce safe and predictable civil engineering structures with existing structural engineering methods. Of the numerous structural forms currently being investigated for civil engineering applications, the truss form appears particularly well suited to fibre composites. The truss is a familiar structural engineering form which possesses certain characteristics that make it well suited to fibre composite materials. In this research a novel monocoque fibre composite truss concept was developed into a working structure and investigated using analytical and experimental methods. To the best of the author's knowledge the research presented in this thesis represents the first doctoral research into a structure of this type. This thesis therefore presents the details of the development of the monocoque fibre composite (MFC) truss concept into a working structure. The developed MFC truss was used as the basis for a detailed investigation of the structural behaviour of the MFC truss elements and the truss as a whole. The static structural behaviour of the principal MFC truss elements (tension members, compression members and joints) was investigated experimentally and analytically. Physical testing required the design and fabrication of a number of novel test rigs. Well established engineering principles were used along with complex finite element models to predict the behaviour of the tested truss elements and trusses. Results of the theoretical analysis were compared with experimental results to determine how accurately their static structural behaviour could be predicted. It was found that the static structural behaviour of all three principal truss elements could be accurately predicted with existing engineering methods and finite element analysis. The knowledge gained from the investigation of the principal truss elements was then used in an investigation of the structural behaviour of the MFC truss. Three full-scale MFC trusses were fabricated in the form of conventional Pratt, Howe and Warren trusses and tested to destruction. The investigation included detailed finite element modelling of the full-scale trusses and the results were compared to the full-scale test results. Results of the investigation demonstrated that the familiar Pratt, Howe and Warren truss forms could be successfully manufactured with locally available fibre composite materials and existing manufacturing technology. The static structural behaviour of these fibre composite truss forms was accurately predicted with well established engineering principles and finite element analysis. A successful marriage between fibre composite materials and a civil engineering structure has been achieved. Monocoque fibre composite trusses have been developed in the familiar Pratt, Howe and Warren truss forms. These structures possess characteristics that make them well suited to applications as primary load bearing structures.
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Lebrão, Guilherme Wolf. "Estudo da viabilidade de fabricação de um tubo para construção de uma prótese de membro inferior em composito híbrido epóxi carbono-vidro." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-25062007-163320/.
Full textAbstract:
Neste trabalho propôs-se a construção de um tubo de material compósito híbrido, com fibra de vidro e fibra de carbono, para utilização como prolongador de prótese de membro inferior a serem fabricadas pela AACD - Associação de Assistência à Criança Deficiente. O objetivo é avaliar as solicitações da prótese para otimizar custo e reduzir a massa. Fez-se inicialmente um levantamento das propriedades dos materiais comerciais utilizados para a fabricação do prolongador para referenciar o desenvolvimento do componente da prótese. Utilizou-se modelagem por elementos finitos para otimizar o componente em função dos esforços biomecânicos a que a prótese é submetida. Nesta modelagem, estudaram-se várias disposições, quantidade e material das camadas de forma a atender às solicitações e minimizar os custos. O levantamento bibliográfico permitiu encontrar uma rota de menor custo para a fabricação de compósito que utiliza um processo de transferência de resina auxiliado a vácuo e pré-formados de vidro e carbono. Como referência, foi fabricado um componente pelo processo de bobinagem filamentar que produz materiais compósitos de qualidade reconhecida. O processo de moldagem por transferência de resina assistido à vácuo, apesar de ter alguns insumos importados, pela sua simplicidade pode ser realizado na própria AACD e se mostrou capaz de obter componentes com custo que viabiliza sua produção sem grandes investimentos em equipamentos. Apesar da redução de algumas das propriedades em relação à peça de referência, o tubo apresentou vantagens na redução de massa e na absorção de impacto.In this work it was considered a construction of a pipe of hybrid composite material, with carbon and glass fibre, for use as prosthesis extension of inferior member to be manufactured for the Associação de Assistência à Criança Deficiente AACD. The objective is to evaluate the requests of prosthesis to optimize cost and to reduce weight. A survey of the properties of the commercial materials commonly used for the manufacture extension became initially a reference to the development of the final component. A finite element modeling was used to optimize the component in the biomechanics function related to the efforts which the prosthesis is submitted. In this modeling some disposals and numbers of layers, amount and material have been studied to take care of the requests and to minimize the cost. A bibliographical survey allowed finding a shipper route for the manufacture of composite that uses a process of vacuum assisted resin transfer molding and preforms of glass with carbon. As reference, a component was produced using filament winding process to compare the quality of the obtained composite pipe. The process, although to have some imported feed-stock, can be proper carried out by AACD and if it showed capable to produce components with cost that makes possible its production internally. Despite the reduction of some of the properties in relation to the reference part, the component presented advantages such as weight reduction and the impact absorption.
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Pristavok, Jan. "Mikromechanische Untersuchungen an Epoxidharz-Glasfaser-Verbundwerkstoffen unter zyklischer Wechselbelastung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2006. http://nbn-resolving.de/urn:nbn:de:swb:14-1166712196632-87749.
Full textAbstract:
Zur Erfassung der mechanischen Eigenschaften im Grenzschichtbereich von Einzelfaser-Modellverbunden und deren Veränderung bei zyklischer Beanspruchung wurde ein elektronisches Mess- und Auswerteverfahren entwickelt. Der Hysteresemessplatz wird bezüglich der Messwerterfassung und Auswertung erweitert und dadurch dessen Messgenauigkeit und Anwendbarkeit verbessert. Im Vergleich zu den zyklischen Untersuchungen anhand des Hysteresemessverfahren (langsamer Einstufenversuch, dynamischer Einstufenversuch, Laststeigerungsversuch) wurden quasistatische Faserauszugtests (Pull-out) [76] durchgeführt. Durch kleine Amplituden von 3 – 4 µm findet die Messung im Bereich des linear-elastischen Materialverhaltens statt, wodurch die gemessenen Eigenschaften im Grenzschichtbereich von der Amplitude unabhängig sind. Kleine Schädigungen treten nur durch zyklische Beanspruchung auf. Somit können die Ermüdungseigenschaften des Einzelfaser-Modellverbundes im Grenzschichtbereich beobachtet werden. Die Einzelfaser-Modellverbunde wurden unter reproduzierbaren Bedingungen auf einer Fasereinbettanlage hergestellt. Der Einzelfaser-Modellverbund stellt eine Abstraktion der Komplexität des makroskopischen Verbundes dar. Dadurch ist eine selektive, lokale Aussage über die mikromechanischen Eigenschaften der Faser-Matrix-Grenzregion ermöglicht. Die in der Grenzschicht zwischen der Glasfaser und der Epoxidharzmatrix hervorgerufene Wechselwirkung wird durch die Oberflächenmodifizierung der Faser beeinflusst. Als Oberflächenmodifizierungen werden Aminopropyltriethoxysilan (APS) in Kombination mit Polyurethan (nicht kompatibel) sowie Epoxid-Filmbildner (kompatibel) betrachtet. Als Modellfälle kommen ungeschlichtete sowie mit Polyvinylacetat geschlichtete Glasfasern zur Anwendung. Als Modellmatrix wird ein reaktives Epoxidharz eingesetzt. Anhand verschiedener Faser-Matrix-Systeme kann festgestellt werden, dass der eingesetzte Haftvermittler eine gute Faser-Matrix-Haftung bewirken, wohingegen Filmbildner die Haftung verschlechtern, insbesondere wenn sie inkompatibel zur verwendeten Matrix sind. Durch unterschiedliche Oberflächenbehandlungen wird die Faser-Matrix-Haftung verändert, was auch zur Veränderung der Ermüdungseigenschaften während der zyklischen Belastung führt. Bei den APS-Proben mit Haftvermittler wurden sehr gute Haftung (hohe Werte für die Scheinbare Scherfestigkeit) zwischen der Glasfaser und der Matrix und gute Ermüdungseigenschaften (geringe Veränderung der Werte für scheinbare Scherfestigkeit, E-Modul etc.) erreicht. Bei den APS/EP-Proben wird durch den Zusatz von Filmbildnern die direkte Verbindung zwischen der Glasfaseroberfläche und der Matrix zum Teil abgeschwächt, was sich im Abfall sowohl der mechanischen Eigenschaften (Abfall de Werte für E-Modul, Steifigkeit etc.) als auch in schlechten Ermüdungseigenschaften widerspiegelt. Der Filmbildner auf Basis von Epoxidharz nimmt offensichtlich während des Herstellungsprozesses an der Vernetzung im Grenzschichtbereich teil und es erfolgt eine gute Interdiffusion der Schlichte in die Matrix. Dies führt dazu, dass APS/EP-Proben im Vergleich zu den APS/PU-Proben ein besseres Eigenschaftsbild aufweisen. APS/PU-Proben zeigen gegenüber ungeschlichteten Fasern eine etwas erhöhte Faser-Matrix-Haftung im Faserauszugstest, jedoch im dynamischen Einstufenversuch ist die Veränderung der Eigenschaften zwischen Anfang und Ende der Messung am größten. Bei der Deformation im Grenzschichtbereich ist bei dem Laststeigerungsversuch ein großer plastischer Anteil vorhanden, was dazu führt, dass das Versagen beim dynamischen Einstufenversuch nicht plötzlich auftritt. Es wird vermutet, dass beim Filmbildner auf Basis von Polyurethan nur eine geringe Interdiffusion in die Epoxidmatrix stattfindet. Bei den PVAc-Proben verleiht der PVAc-Filmbildner der Grenzschicht ebenfalls, trotz geringer Haftung zwischen Faser und Matrix, eine gewisse Plastizität und Fähigkeit, Energie zu dissipieren. Diese Eigenschaft der Schlichte kann auch bei den Laststeigerungsversuchen beobachtet werden. Die schwache Haftung führt jedoch beim Faserauszugtest zu kleinen scheinbaren Scherfestigkeiten. Ungeschlichtete Glasfasern bilden keine signifikante Faser-Matrix-Haftung, verbessert durch Wechselwirkung, aus, die der Dauerbelastung stand halten. Sehr kleine Werte für scheinbare Scherfestigkeiten im Faserauszugtest gehen konform mit einem spröden Versagen im Grenzschichtbereich, was sich in einem plötzlichen Abfall der Eigenschaften bei zyklischer Belastung bemerkbar macht. Im Vergleich zu den zyklischen Untersuchungen an Einzelfaser-Modellverbunden ergeben quasistatische Untersuchungen, bedingt durch die Signifikanz der Grenzschicht, gleiche Tendenzen. Eine gute Korrelation kann zu den Ergebnissen des statischen Querzugversuches an Unidirektionalverbunden festgestellt werden, da hier ebenfalls die Grenzschicht einen dominanten Einfluss ausübt. Die zyklische Wechselbelastung der unidirektionalen Zugprüfkörper reflektiert neben dem Grenzschichteinfluss sehr stark die Faserfestigkeit sowie Probleme des Lasteintrages, die nur bedingt mit einem Debonding sowie einem Scherversagen in der Grenzschicht verglichen werden kann. Bedingt durch unterschiedliche „Dehnbarkeit“ im Grenzschichtbereich (in der Grenzschicht) können Korrelationen zu den mikromechanischen Versuchsergebnissen bei zyklischer Wechselbelastung festgestellt werden. Zusammenfassend kann eingeschätzt werden, dass die hohe Empfindlichkeit des Hysteresemessverfahrens es ermöglicht, in kurzer Zeit den Einfluss verschiedener Oberflächenmodifizierungen zu beurteilen und damit eine Vorauswahl über die im Verbund gebildeten Grenzschichten zu treffen.
38
Pristavok, Jan. "Mikromechanische Untersuchungen an Epoxidharz-Glasfaser-Verbundwerkstoffen unter zyklischer Wechselbelastung." Doctoral thesis, Technische Universität Dresden, 2005. https://tud.qucosa.de/id/qucosa%3A24914.
Full textAbstract:
Zur Erfassung der mechanischen Eigenschaften im Grenzschichtbereich von Einzelfaser-Modellverbunden und deren Veränderung bei zyklischer Beanspruchung wurde ein elektronisches Mess- und Auswerteverfahren entwickelt. Der Hysteresemessplatz wird bezüglich der Messwerterfassung und Auswertung erweitert und dadurch dessen Messgenauigkeit und Anwendbarkeit verbessert. Im Vergleich zu den zyklischen Untersuchungen anhand des Hysteresemessverfahren (langsamer Einstufenversuch, dynamischer Einstufenversuch, Laststeigerungsversuch) wurden quasistatische Faserauszugtests (Pull-out) [76] durchgeführt. Durch kleine Amplituden von 3 – 4 µm findet die Messung im Bereich des linear-elastischen Materialverhaltens statt, wodurch die gemessenen Eigenschaften im Grenzschichtbereich von der Amplitude unabhängig sind. Kleine Schädigungen treten nur durch zyklische Beanspruchung auf. Somit können die Ermüdungseigenschaften des Einzelfaser-Modellverbundes im Grenzschichtbereich beobachtet werden. Die Einzelfaser-Modellverbunde wurden unter reproduzierbaren Bedingungen auf einer Fasereinbettanlage hergestellt. Der Einzelfaser-Modellverbund stellt eine Abstraktion der Komplexität des makroskopischen Verbundes dar. Dadurch ist eine selektive, lokale Aussage über die mikromechanischen Eigenschaften der Faser-Matrix-Grenzregion ermöglicht. Die in der Grenzschicht zwischen der Glasfaser und der Epoxidharzmatrix hervorgerufene Wechselwirkung wird durch die Oberflächenmodifizierung der Faser beeinflusst. Als Oberflächenmodifizierungen werden Aminopropyltriethoxysilan (APS) in Kombination mit Polyurethan (nicht kompatibel) sowie Epoxid-Filmbildner (kompatibel) betrachtet. Als Modellfälle kommen ungeschlichtete sowie mit Polyvinylacetat geschlichtete Glasfasern zur Anwendung. Als Modellmatrix wird ein reaktives Epoxidharz eingesetzt. Anhand verschiedener Faser-Matrix-Systeme kann festgestellt werden, dass der eingesetzte Haftvermittler eine gute Faser-Matrix-Haftung bewirken, wohingegen Filmbildner die Haftung verschlechtern, insbesondere wenn sie inkompatibel zur verwendeten Matrix sind. Durch unterschiedliche Oberflächenbehandlungen wird die Faser-Matrix-Haftung verändert, was auch zur Veränderung der Ermüdungseigenschaften während der zyklischen Belastung führt. Bei den APS-Proben mit Haftvermittler wurden sehr gute Haftung (hohe Werte für die Scheinbare Scherfestigkeit) zwischen der Glasfaser und der Matrix und gute Ermüdungseigenschaften (geringe Veränderung der Werte für scheinbare Scherfestigkeit, E-Modul etc.) erreicht. Bei den APS/EP-Proben wird durch den Zusatz von Filmbildnern die direkte Verbindung zwischen der Glasfaseroberfläche und der Matrix zum Teil abgeschwächt, was sich im Abfall sowohl der mechanischen Eigenschaften (Abfall de Werte für E-Modul, Steifigkeit etc.) als auch in schlechten Ermüdungseigenschaften widerspiegelt. Der Filmbildner auf Basis von Epoxidharz nimmt offensichtlich während des Herstellungsprozesses an der Vernetzung im Grenzschichtbereich teil und es erfolgt eine gute Interdiffusion der Schlichte in die Matrix. Dies führt dazu, dass APS/EP-Proben im Vergleich zu den APS/PU-Proben ein besseres Eigenschaftsbild aufweisen. APS/PU-Proben zeigen gegenüber ungeschlichteten Fasern eine etwas erhöhte Faser-Matrix-Haftung im Faserauszugstest, jedoch im dynamischen Einstufenversuch ist die Veränderung der Eigenschaften zwischen Anfang und Ende der Messung am größten. Bei der Deformation im Grenzschichtbereich ist bei dem Laststeigerungsversuch ein großer plastischer Anteil vorhanden, was dazu führt, dass das Versagen beim dynamischen Einstufenversuch nicht plötzlich auftritt. Es wird vermutet, dass beim Filmbildner auf Basis von Polyurethan nur eine geringe Interdiffusion in die Epoxidmatrix stattfindet. Bei den PVAc-Proben verleiht der PVAc-Filmbildner der Grenzschicht ebenfalls, trotz geringer Haftung zwischen Faser und Matrix, eine gewisse Plastizität und Fähigkeit, Energie zu dissipieren. Diese Eigenschaft der Schlichte kann auch bei den Laststeigerungsversuchen beobachtet werden. Die schwache Haftung führt jedoch beim Faserauszugtest zu kleinen scheinbaren Scherfestigkeiten. Ungeschlichtete Glasfasern bilden keine signifikante Faser-Matrix-Haftung, verbessert durch Wechselwirkung, aus, die der Dauerbelastung stand halten. Sehr kleine Werte für scheinbare Scherfestigkeiten im Faserauszugtest gehen konform mit einem spröden Versagen im Grenzschichtbereich, was sich in einem plötzlichen Abfall der Eigenschaften bei zyklischer Belastung bemerkbar macht. Im Vergleich zu den zyklischen Untersuchungen an Einzelfaser-Modellverbunden ergeben quasistatische Untersuchungen, bedingt durch die Signifikanz der Grenzschicht, gleiche Tendenzen. Eine gute Korrelation kann zu den Ergebnissen des statischen Querzugversuches an Unidirektionalverbunden festgestellt werden, da hier ebenfalls die Grenzschicht einen dominanten Einfluss ausübt. Die zyklische Wechselbelastung der unidirektionalen Zugprüfkörper reflektiert neben dem Grenzschichteinfluss sehr stark die Faserfestigkeit sowie Probleme des Lasteintrages, die nur bedingt mit einem Debonding sowie einem Scherversagen in der Grenzschicht verglichen werden kann. Bedingt durch unterschiedliche „Dehnbarkeit“ im Grenzschichtbereich (in der Grenzschicht) können Korrelationen zu den mikromechanischen Versuchsergebnissen bei zyklischer Wechselbelastung festgestellt werden. Zusammenfassend kann eingeschätzt werden, dass die hohe Empfindlichkeit des Hysteresemessverfahrens es ermöglicht, in kurzer Zeit den Einfluss verschiedener Oberflächenmodifizierungen zu beurteilen und damit eine Vorauswahl über die im Verbund gebildeten Grenzschichten zu treffen.
39
LI, SHI-TENG, and 李士騰. "Glass fiber reinforced polyurethane / epoxy graft interpenetrating polymer networks." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/25473227132164137855.
Full text
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Wang, 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.
Full text
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Liu, 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.
Full textAbstract:
碩士國立勤益科技大學
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.
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顏俊成. "Research on pultrusion of glass fiber reinforced blocked polyurethane modified epoxy resins." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/70490001963271276713.
Full textAbstract:
碩士中國文化大學
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％.
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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.
Full textAbstract:
碩士國立交通大學
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.
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彭運娟. "A study of vibration damping properties on glass fiber reinforced epoxy resin." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/65799715135687674279.
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PENG, 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.
Full textAbstract:
碩士中華大學
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.
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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.
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碩士長庚大學
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.
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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.
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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.
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CHUEH, 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.
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碩士逢甲大學
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.
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(10725372), Rajan Nitish Jain. "Intrinsic Self-Sensing of Pulsed Laser Ablation in Carbon Nanofiber-Modified Glass Fiber/Epoxy Laminates." Thesis, 2021.
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Laser-to-composite interactions are becoming increasingly common in diverse applications such as diagnostics, fabrication and machining, and weapons systems. Lasers are capable of not only performing non-contact diagnostics, but also inducing seemingly imperceptible structural damage to materials. In safety-critical venues like aerospace, automotive, and civil infrastructure where composites are playing an increasingly prominent role, it is desirable to have means of sensing laser exposure on a composite material. Self-sensing materials may be a powerful method of addressing this need. Herein, we present an exploratory study on the potential of using changes in electrical measurements as a way of detecting laser exposure to a carbon nanofiber (CNF)-modified glass fiber/epoxy laminate. CNFs were dispersed in liquid epoxy resin prior to laminate fabrication via hand layup. The dispersed CNFs form a three-dimensional conductive network which allows for electrical measurements to be taken from the traditionally insulating glass fiber/epoxy material system. It is expected that damage to the network will disrupt the electrical pathways, thereby causing the material to exhibit slightly higher resistance. To test laser sensing capabilities, a resistance baseline of the CNF-modified glass fiber/epoxy specimens was first established before laser exposure. These specimens were then exposed to an infra-red laser operating at 1064 nm, 35 kHz, and pulse duration of 8 ns. The specimens were irradiated for a total of 20 seconds (4 exposures each at 5 seconds). The resistances of the specimens were then measured again post-ablation. In this study, it was found that for 1.0 wt.% CNF by weight the average resistance increased by about 18 percent. However, this values varied for specimens with different weight fractions. This established that the laser was indeed causing damage to the specimen sufficient to evoke a change in electrical properties. In order to expand on this result, electrical impedance tomography (EIT) was employed for localization of laser exposures of 1, 3, and 5 seconds on a larger specimen, a 3.25” square plate. EIT was used to measure the changes in conductivity after each exposure. EIT was not only successful in detecting damage that was virtually imperceptible to the human-eye, but it also accurately localized the exposure sites. The post-ablation conductivity of the exposure sites decreased in a manner that was comparable to the resistance increase obtained during prior testing. Based on this preliminary study, this research could lead to the development of a real-time exposure detection and tracking system for the measurement, fabrication, and defense industries.