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 48 for “"fracture model"”.
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Application of the Variational Fracture Model to Hydraulic Fracturing in Poroelastic Media
… persisted through the use of simple numerical models to describe fracture geometry and propagation. Field tests provide evidence of interaction and merging of multiple fractures, complex fracture geometry and propagation paths. These complicated behaviors suggest that the simple models are …
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An integrated peridynamics-finite volume based multi-phase flow, geomechanics and hydraulic fracture model
… phenomena including the interaction of hydraulic fractures with multi-scale heterogeneities such as natural fractures, stress/barrier layers, bedding planes, shale laminations, and mineralogy. Moreover, hydraulic fractures originating from different clusters or stages in a multi-stage, …
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Simulating water tracer test in naturally fractured reservoirs using discrete fracture and dual porosity models
A naturally fractured reservoir (NFR) is a reservoir with a connected network of fractures created by natural processes such as diastrophism and volume shrinkage (Ordonez et al. 2001). There are two models to simulate this kind of reservoirs: the discrete fracture model and the dual porosity model. …
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Crack Initiation Analysis in Residual Stress Zones with Finite Element Methods
… nearly untapped research area of the analysis of fracture mechanics in residual stress zones. This type of research has become more prevalent in the field in recent years due to the increase in prominence of residual stress producing processes. Such processes include additive manufacturing of …
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Healing of Bone Fracture in Type 1 Diabetic Rat Models: a Potential Gene Therapy Using Bone Morphogenetic Protein
… related comorbidities, low-energy-trauma fracture is one of the major causes of morbidity and mortality of patients, due to the increased fracture risk in comparison with normal group and the impaired healing procedure after fracture. Bone morphogenetic proteins are well-known for their …
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MECHANISTIC STUDY OF CRACK INITIATION AND PROPAGATION IN CROSSLINKED ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENES (UHMWPE) SUBJECTED TO STATIC AND CYCLIC LOADING
… vivo mechanical loads. Reports suggest that the fracture resistance of UHMWPE could be improved which can help the longevity of the components in vivo. Fatigue crack propagation behavior of two crosslinked UHMWPE formulations was investigated to estimate the mechanical governing factor for stable …
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The influence of high performance matrices on fracture behavior of concrete
… strength of concrete, but its contributions to fracture behavior remains unclear. In this study, the influence of replacing cement by silica fume and fly ash on the cement matrix-coarse aggregate interfacial bond, compressive stress-strain behavior and fracture behavior of concrete is …
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Micromechanics of strength-related phenomena in composite materials
Micromechanical models are presented which can be used to evaluate: stress concentrations 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 …
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Prediction of service load of concrete structures after cracking using ultrasonic technique
… study is to investigate the cracking behavior of fractured concrete structures and to introduce a new approach to assess their remaining service lives. A novel ultrasonic technique is utilized to detect crack propagation in notched beams of mortar, plain concrete and reinforced concrete. The study …
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Fracture Behavior of Masonry Bond
The applied fracture mechanics model, when both elastic and inelastic deformations were considered, always over-estimated the post-peak behavior. However, the post-peak behavior was successfully predicted when the model was modified to consider only elastic deformation. The analysis indicated that …
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Fracture mechanics of volcanic eruptions
… reach the surface. Time-to-failure forecasting models have been shown to be consistent with seismic acceleration patterns prior to eruptions at volcanoes in subduction zone settings. The aim of this research is to investigate the patterns in seismic activity produced by a failure model based on …
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Dispersion of graphene nanoplatelets in water with surfactant and reinforcement of mortar with graphene nanoplatelets
… then analyzed in keeping with the two-parameter fracture model. The mechanical results were inconclusive, but they suggested a path forward to continued research.
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Paint-bake effect on the plasticity and fracture of pre-strained aluminum 6451 sheets
… characterize the anisotropic plasticity and the fracture initiation in prestrained artificially-aged aluminum 6451 sheets. It is found that the combination of pre-straining up to 5% strain and heat treatment mainly changes the material's strain hardening behavior and the stress-state sensitivity …
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A Dislocation-Based Constitutive Model for Hydrogen-Deformation Interactions and a Study of Hydrogen-Induced Intergranular Fracture
This thesis presents two models of the effect of hydrogen on materials. Both models are intended to link experimental observations of material microstructure with macroscopically observable results. The first model creates a continuum, rate dependent plasticity model that incorporates the effect of …
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A dislocation-based constitutive model for hydrogen—deformation interactions and a study of hydrogen-induced intergranular fracture
This thesis presents two models of the effect of hydrogen on materials. Both models are intended to link experimental observations of material microstructure with macroscopically observable results. The first model creates a continuum, rate dependent plasticity model that incorporates the effect of …
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Fracture and plasticity characterization of DH-36 Navy steel
… and simulation was performed to characterize fracture and plasticity of DH-36 Navy steel, which is the first step in creating an accurate model of the composite material. The performance limit to this material during an impact is ductile fracture. The prediction follows that the onset of …
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Modelling of thermo-mechanical and irradiation behavior of metallic and oxide fuels for sodium fast reactors
A robust and reliable code to model the irradiation behavior of metal and oxide fuels in sodium cooled fast reactors is developed. Modeling capability was enhanced by adopting a non-empirical mechanistic approach to the extent possible, so that to increase the ability to extrapolate the existing …
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Characterization and Assessment of Lung and Bone Marrow Derived Endothelial Cells and their Bone Regenerative Potential
Fracture repair is costly and difficult to treat. One of the main causations of nonunion is a lack of essential blood supply. The needed blood is supplied by the growth of new blood vessels, a process known as angiogenesis, that invade the damaged tissue early in the healing process. We proposed …
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Fracture healing : the effects of local insulin delivery via calcium sulfate and tricalcium phosphate
… local intramedullary insulin delivery to the fracture site and its effect upon the normal fracture healing process. Preceding results show that when administered at the fracture site of the impaired fracture healing model of the diabetic BB Wistar rat, insulin will regulate early cellular …
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Fiber Orientation Effects on the Fracture and Flexural Toughness of Extruded Fiber Reinforced Concrete for Additive Manufacturing
… toughness based on load-deflection curves. The fracture properties of FRCC were determined by using three-point bend tests on the same design but having notched beams using the two-parameter fracture model (TPFM). Calculations included the Mode I critical stress intensity factor (KIC), the …
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