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HYDRAULIC FRACTURING USING A MODIFIED BOREHOLE DEFORMATION GAGE IN THE TEST INTERVAL.Dischler, Steven Anthony. January 1984 (has links)
No description available.
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Characterization of multiaxial fracture strength of transversely isotropic agot graphiteHackerott, H. Alan January 2011 (has links)
Vita. / Digitized by Kansas Correctional Industries
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Three dimensional nonlinear finite element stress analysis of a lumbar intervertebral jointShirazi-Adl, Aboulfazl January 1984 (has links)
No description available.
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Evaluation of the torsion test for determining the shear strength of structural lumberHeck, Leanne Renee 06 November 1997 (has links)
The torsion test was evaluated as a method for determining the shear
strength of full-size structural lumber. The evaluation involved an experimental
length study, an experimental depth study, and a finite element study.
The length study consisted of fifty nominal 2x4 specimens, ten specimens
for each length, and ten American Society for Testing and Materials (ASTM)
shear blocks. One 14 foot long board yielded one specimen for each length: (a)
21.0", (b) 28.5", (c) 32.0", (d) 35.5", (e) 39.0", and (f) an ASTM D143-94 shear
block. The statistical analysis revealed no evidence that the length affected the
shear strength.
The depth study consisted of fifty specimens, ten specimens for each
depth: (a) 2x4, (b) 2x6, (c) 2x8, (d) 2x10, and (e) 2x12. In addition, fifty ASTM
shear blocks, one block for each specimen, were tested. The statistical study did not reveal convincing evidence of a depth effect on shear strength, even
after accounting for specific gravity and shear span as covariates.
Failure modes for the torsion samples involved a longitudinal shear crack
at the mid-point of the longest side, which propagated toward the ends of the
specimen and through the cross section perpendicular to the growth rings.
The finite element model revealed that uniform shear stress occurs within
the shear span, which begins and ends a distance of approximately two times
the depth plus the grip distance away from each end of the member. In addition,
torsion theory verified that the experimental shear failure plane that occurs
within the shear span is parallel to the grain and the shear slippage is also
parallel to the grain, similar to the known shear failure in specimens subjected to
bending loads.
Based on the results of this study, the torsion test is the best practical
method to determine the pure shear strength of full-size structural lumber,
because the test yields 100% shear failures and the specimen is in a state of
pure shear stress. / Graduation date: 1998
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Three dimensional nonlinear finite element stress analysis of a lumbar intervertebral joint / 3-D nonlinear finite element stress analysis of a lumbar intervertebral joint.Shirazi-Adl, Aboulfazl January 1984 (has links)
The need for the development of a rigorous analytical model of the lumbar spine to clarify the role of mechanical factors in low-back disorders has long been recognized. In response to this need, a general three dimensional nonlinear finite element program has been developed as part of this work and has been applied to the analysis of a lumbar L(,2-3) joint including the posterior elements. The analysis accounts for both the material and geometric nonlinearities and is based on a representation of the nucleus as an incompressible inviscid fluid and of the annulus as a composite of collagenous fibres embedded in a matrix of ground substance. The facet articulation has been accounted for by treating it as a general moving contact problem. The ligaments have been modelled as a collection of nonlinear axial elements. The geometry of the finite element model is based on in-vitro measurements. / The response of the joint under single compression, single flexion, single extension and also under flexion or extension combined with compression and sagittal shear has been analyzed for both the normal and degenerated states of the nucleus. Validity of the model has then been established by a comparison of those predictions which are also amenable to direct measurements. The states of strain and stress in different components of the lumbar joint have been thoroughly studied under all the foregoing loading conditions. / Those elements of the joint predicted to be vulnerable to mechanical failure or damage under the above types of loading have been identified. These results have been correlated with the lumbar joint injuries reported clinically. Furthermore, some joint injury mechanisms and degeneration processes have been proposed and the supporting clinical evidences have been presented.
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Development of the EBSD Intensity Response for Quantitative Strain Analyses of MaterialsCocle, Jennifer January 2008 (has links)
No description available.
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Development of the EBSD Intensity Response for Quantitative Strain Analyses of MaterialsCocle, Jennifer January 2008 (has links)
Electron BackScattered Diffraction (EBSD) systems can be considered as a tool providing three kinds of responses: EBSD patterns (EBSPs) themselves, an indexing response (orientation data), and an intensity response (also called Band Contrast "BC", Image Quality "IQ", or Pattern Quality "PQ or P"). This work focused on the characterization and development of the intensity response. For now, the intensity response cannot be used for quantitative microstructural analyses, including strain analyses of materials. Indeed, this response is affected by several material and experimental conditions. Moreover, properties of the intensity response (strain sensitivity, reproducibility, exact relation with EBSP quality or diffraction band intensities) are not well-known and understood. This project constitutes an exploratory study on the development of the intensity response for quantitative strain analyses of materials. A new modelling and statistical approach is presented and assessed for transforming the raw (current) intensity response (values and grey-tones of intensity images) of commercial EBSD systems into an accurate and reproducible parameter allowing objective visualization and measurements of strain. / Les systèmes de diffraction des électrons rétro-diffusés (EBSD) peuvent être considérés comme un outil offrant trois types de réponses: les patrons EBSD (EBSPs), la réponse d'indexation (données d'orientation) et la réponse d'intensité (aussi appelée Contraste de Bande «BC », Qualité d'Image « IQ », ou Qualité de Patron « PQ ou P »). Le présent projet s'est concentré sur la caractérisation et le développement de la réponse d'intensité. En effet, pour l'instant, la réponse d'intensité ne peut être utilisée pour réaliser des analyses microstructurales quantitatives des matériaux. En effet, cette réponse est influencée par de nombreux facteurs relatifs au matériau analysé et aux conditions expérimentales utilisées. De plus, les propriétés de la réponse d'intensité (sensibilité à la déformation, reproductibilité, relation exacte avec la qualité des EBSPs ou les intensités des bandes de diffraction) ne sont pour l'instant pas bien connues ni même compnses. Le présent projet représente donc une étude exploratoire visant le développement de la réponse d'intensité des systèmes EBSD commerciaux pour l'analyse quantitative de la déformation des matériaux. Dans ce projet, une approche de modélisation statistique est présentée et évaluée afin de transformer la réponse d'intensité actuelle (valeurs et tons de gris des images d'intensité) des systèmes EBSD commerciaux en une réponse précise et reproductible permettant de visualiser et de mesurer objectivement la déformation.
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Distributed plasticity analysis of steel building structural systemsAlemdar, Bulent Nedim 08 1900 (has links)
No description available.
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