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 105 for “"plies"”.
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Modeling and manufacturing of adaptive plates incorporating piezoelectric fiber composite plies
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1995.
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Germinal Ideas and Processes within plies (2002): A Chamber Work for Eleven Players
… of jazz music informed the construction of plies, including the instrumentation of the ensemble and the means by which the performers interact throughout the piece. Internal cueing and performer decisions are meant to eliminate the need of a conductor in favor of increased interpretive …
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Response and failure analysis of a graphite-epoxy laminate containing terminating internal plies
… laminate thickness due to terminating internal plies acts as a stress riser for both intralamina and interlaminar stresses. This laminate configuration is referred to as a ply drop. The linear elastic, three-dimensional stress distributions in the vicinity of a ply drop are determined for a …
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Damage and failure mechanisms under fatigue in long fibre composites with ultra-thin plies
El estudio del comportamiento a fatiga de los materiales compuestos es de gran interés en el ámbito científico debido al carácter no estático de las cargas que sufre una estructura en servicio. En los últimos años, la aparición de láminas ultradelgadas, de hasta 15 20 μm de espesor, ha tomado …
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A characterization of the fracture behavior of thick, notched, laminated graphite/epoxy composites
… with thicknesses of 8, 32, 64, 96 and 120 plies and the [0/±45]<sub>ns</sub> laminate with thicknesses of 6, 30, 60, 90 and 120 plies. The research concentrated on the measurement of fracture toughness utilizing the center-cracked tension, compact tension and three point bend specimen …
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Scaling Effects on Damage Development, Strength, and Stress-Rupture Life on Laminated Composites in Tension
… First-ply failure of the midplane 90 deg. plies depended on the stiffness of constraint plies, and size. All 24 cases were predicted using Zhang's shear-lag model and data generated from cross-ply tests. Laminate strength was controlled by the initiation of a triangular-shaped local …
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Finite element analysis of composite tubes with integral ends subjected to bending loads
… to predict stresses within the individual plies of the tubes. The tubes under investigation were graphite/epoxy laminated composites with a stacking sequence of [0/-45/+45/90/90/+45/ -45/0] X 2 (Sixteen plies per tube). End pieces of isotropic titanium were integrally constructed with …
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Local and Global Sensitivity Analysis of Thin Ply Laminated Carbon Composites
… strength of laminates constructed from very thin plies. Interlaminar shear and normal stress components have been shown to be concentrated on the edges, the so-called edge effect, of unidirectional laminates at the interface between plies of different fiber orientation. Research has shown that …
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Lateral Torsional Buckling of Built-Up Beams
… timber beams are composed of multiple thin plies of equal depth, mechanically connected along their vertical interfaces using discrete fasteners to provide partial composite action. These beams are increasingly used in modern timber structures because thin plies are more economical and more …
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Effect of ply drop-offs on the strength of graphite-epoxy laminates
… of a graphite-epoxy laminate due to dropping plies is investigated experimentally and analytically. Laminates were tested under uniaxial tension and compression. All the laminates were flat on one side with the plies dropped from the middle of a [( ± 45/0/90)<sub>s</sub> (N<sub>d</sub>) ( ± …
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Delamination initiation in postbuckled dropped-ply laminates
… the interfaces above and/or below the dropped plies is a common mode of failure initiation. The compression strength of specimens exhibiting a linear response is greater than the compression strength of specimens with the same layup exhibiting geometrically nonlinear response. Experimental and …
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Investigation of constraint effects on flaw growth in composite laminates
… and spacing of transverse cracks in the off-axis plies to form a characteristic damage state in the laminates. Out-of-plane stresses produced by constraints are influential on the growth of damage along ply interfaces, especially during cyclic loading. The mode of damage and the extent of damage …
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Large deformation dynamic bending of composite beams
… tested were 23 in. by 2 in. and generally 30 plies thick. The beams were loaded dynamically with a gravity-driven impactor traveling at 19.6 ft./sec. and quasi-static tests were done on identical beams in a displacement controlled manner. For laminates of practical interest, the failure modes …
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Effects of Corrugations on Stiffness Properties of Composite Beams for Structural Applications
… The FG laminates were manufactured from four plies of pre-impregnated Cytec MXB 7701/7781. The CF laminate consisted of five plies of pre-impregnated unidirectional Tencate TC250/M46J. The layup orientation of the CF laminate had alternating 0◦ and 90◦ plies, where the 0 ◦ plies were in the …
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Role of delamination and interlaminar fatigue in the failure of laminates with ply dropoffs
… taper angle and the location of the terminated plies are found to affect the interlaminar stress distribution. Careful consideration of the characteristics and trends of the interlaminar stresses in such laminates reveals that two fundamental mechanisms give rise to interlaminar stresses: the …
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The effect of thickness on the fracture behavior of graphite/bismaleimede laminates with central circular holes
… specimens exhibited matrix cracking in the 90° plies around the hole and vertical splitting in the 0° plies at the edge of the hole.
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Multi-scale analysis of wrinkling during consolidation of thermoset composites
… between these factors and the wrinkling of plies caused by micro-buckling has not been investigated quantitatively. Furthermore, these effects are not fully captured in current process models. This research aims to develop an efficient strategy for analysing the multi-scale mechanisms of …
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Effects of Shallow Bi-Angle, Thin-Ply Laminates on the Structural Performance of Composite Wings
… we find that shallow bi-angle fibers and thin plies can increase the axial stiffness of laminates significantly at the cost of relatively small decrease in their transverse and shear moduli. For the structural tests, we fabricate composite wing structures using an out-of-autoclave vacuum …
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A methodology for the automation of dry fabric layup for fiber reinforced polymer composite manufacturing
… shearing for the layup of Non-Crimp Fabric (NCF) plies for 2-dimensional and 3-dimensional composite components. This research includes the development of a machine capable of imparting shear on NCF plies. Results are presented with an equation for calculating machine settings for a given …
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New in-plane and interlaminar shear test methods for fiber reinforced composites
… The interlaminar shear modulus of individual plies and the effective modulus for the laminate were determined. Variations of nominally equal plies were observed.
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