Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 62 for “"Fiber Volume Fraction"”.
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Experimental and theoretical investigation of the curing process of thermosetting composite structures with angle-bend
… degree of cure, viscosity, compaction and fiber volume fraction were examined. A first set of experiments was done to investigate the effect of different curing cycles on temperature exotherms, thickness variation and fiber volume fraction distribution. Results from both simulation and …
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Plug repairs of marine glass fiber / vinyl ester laminates subjected to uniaxial tension
Glass fiber/vinyl ester composite laminates are currently being used and proposed for the hulls, bulkheads, and superstructures of large ships. This thesis examines the effectiveness of the repair of such laminates using glass fiber/vinyl ester chopped strand mat plugs to fill circular holes. The …
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The Comparison of Composite Aircraft Field Repair Method (CAFRM) with Traditional Aircraft Repair Technologies
… able to determine the specimen's void content, fiber volume fraction, shear strength, and opening mode interlaminar fracture toughness for the specimens fabricated using the different repair methods. The specimens fabricated using the autoclave repair method, DVD repair method, and CAFRM showed …
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Improving the Quality of Laminates in Liquid Composite Molding Using Magnetic Compaction: Experiments and Process Model
… they have two major drawbacks. First, the fiber volume fraction of the composite parts made by LCM is lower than those made under an elevated pressure using either autoclave or hot press, leading to lower mechanical properties. Second, the process induced defects in LCM parts are quite …
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Manufacturing Quality of Carbon/Epoxy IsoTruss (R) Reinforced Concrete Structures
… m) long IsoTruss® grid structures manufactured. Fiber volume fraction, void fraction, and cross section area inspections were performed on IsoTruss® samples to determine quality. The strength, stiffness, and fiber volume fraction data obtained from these tests are compared to values obtained …
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The structure and mechanical behavior of bamboo and bamboo products
… and vascular bundles, consisting of sclerenchyma fibers and vessels; the structure can be thought of as a fiber reinforced composite. There is a radial gradient in the volume fraction of vascular bundles as well as the fraction of quite solid sclerenchyma fibers within the vascular bundles, …
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Plug repairs of marine glass fiber / vinyl ester laminates subjected to in-plane shear stress or in-plane bending moment
Glass fiber / vinyl ester composite laminates represent an important class of modem fiber composites being proposed or used in state-of-the-art shipbuilding. This thesis examined the effectiveness of chopped strand mat (CSM) plug repairs of glass fiber / vinyl ester woven roving laminates subjected …
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Verification of a two-dimensional infiltration model for the resin transfer molding process
… which is based on the finite element/control volume technique, determines the total infiltration time and the pressure increase at the mold inlet associated with the RTM process. Important input data for the model are the compaction and permeability behavior of the preform along with the …
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A study of two dimensional braided composites
… model of 2-D braided composite is developed. The fiber volume and crimp angle are evaluated by this model and are compared with experimental results. The maximum fiber volume fraction is also obtained. Effective stiffness of 2-D braided composite is obtained in a close form by the analysis of …
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Mechanical Properties of Random Discontinuous Fiber Composites Manufactured from Wetlay Process
The random discontinuous fiber composite has uniform properties in all directions. The wetlay process is an efficient method to manufacture random discontinuous thermoplastic preform sheets that can be molded into random composite plaques in the hot-press. Investigations were done on the molding …
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Mechanical properties of bio-absorbable materials
… Poly-e-caprolactone (PCL), matrices with Carbon fibers (AS4), Nylon fibers and PLLA fibers. Fiber coating effects have also been investigated, with compliant polymers (1%, 50% and 100% of matrix properties) and with hydroxyapatite (HA). Unidirectional, continuous fiber plies, and …
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Hierarchical carbon fiber composites with radially aligned carbon nanotubes : preservation of in-plane tensile properties
… on woven alumina filaments to form a "fuzzy fiber" reinforced plastic (FFRP) architecture with demonstrated improvements in inter- and intra-ply mechanical properties as well as multifunctional enhancement via tailorable electrical and thermal conductivities. However, thus far, the …
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Forced vibration and hygrothermal analysis of composite laminated beams under the action of moving loads
… A parametric study is conducted by varying the fiber volume fraction and the fiber orientation of the angle plies in the laminate. The results indicate that the dynamic magnification factors generally increase due to hygrothermal effects but all the laminates considered do not behave in a …
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Micromechanics of strength-related phenomena in composite materials
… in the vicinity of single and multiple fiber fractures in unidirectional composites under axial loading; the tensile strength of unidirectional composites; fiber coatings that can be used to maximize the transverse strain-to-failure and longitudinal shear strain-to-failure of composites; …
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Numerical Constitutive Models of Woven and Braided Textile Structural Composites
… plain weave architecture, equations for the fiber volume fraction and the cross-sectional shape of the yarn are derived for large crimp angles. It is shown that the maximum crimp angle is limited to forty-five degrees, and that limits on the ratio of the length of the undulation portion of …
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Measurement of ultrasonic wave mode transition in unidirectional graphite/epoxy composites
… of T300/5208 graphite/epoxy composite with a 0.6 fiber volume fraction. The mode transition occurs at 51.85° wave vector orientation with respect to the fiber direction. Energy flux deviation and particle displacement directions and amplitudes were also compared with theory. To show this mode …
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Processing parameters and chamber length impact on detached die and attached die resin injection pultrusion
… process for high-quality, low-cost, high-volume manufacturing of composites. The main objective of this study is to analyze "attached die configuration" and "detached die configuration" for the better injection pultrusion process. In this work the impact of various processing parameters on …
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Assessment of dielectric models and their application to polymer matrix composites
… of the spheres into the structure, E-glass fibers, at low fiber volume fraction, were added. The dielectric response of the epoxy-ceramic spheres-glass fibers system was studied, and it was found that this type of composite structure can be used to produce materials with tailored dielectric …
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Modeling the microwave frequency permittivity of thermoplastic composite materials
… frequency permittivities of unidirectional-fiber-reinforced thermoplastic-matrix composite materials as a function of fiber volume fraction, fiber orientation relative to the electric field, and temperature. The permittivities of the constituent fiber and plastic materials were measured …
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Micromechanics of finite length fibers in composite materials
… occur in the constituents of a hybrid 3-D short fiber composite subjected to arbitrary homogeneous loading conditions. The model includes the capability to analyze composites containing different types of fibers, different aspect ratios of fibers (as well as continuous fibers), and different …
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