You searched for subject:(fracture).
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1.
Lyons, John.
A Novel Model for Fracture Acidizing with Important Thermal Effects.
Degree: 2013, Texas Digital Library
URL: http://hdl.handle.net/1969; 
http://hdl.handle.net/2249.1/66577
► Fracture acidizing is a well stimulation technique used to improve the productivity of low-permeability reservoirs, and to bypass deep formation damage. The reaction of injected…
(more)
▼ Fracture acidizing is a well stimulation technique used to improve the productivity of low-permeability reservoirs, and to bypass deep formation damage. The reaction of injected acid with the rock matrix forms etched channels (that depend on injection rate, mass transport properties, formation mineralogy, reaction chemistry of the acid, and temperature) through which oil and gas can then flow upon production.
The use of a model that can effectively describe
fracture acidizing is an essential step in designing an efficient and economical treatment. Several studies have been conducted on modeling
fracture acidizing, however, most of these studies have not accounted for the effect of variation in acid temperature (by heat exchange with the formation and the heat generated by acid reaction with the rock) on reaction rate and mass transfer of acid inside the
fracture.
In this study, a new
fracture acidizing model is presented that uses the lattice Boltzmann method for fluid transport and takes into account these temperature effects. The lattice Boltzmann method incorporates both accurate hydrodynamics and reaction kinetics at the solid-liquid interface. This method is also well known for its capability to handle re- active transport in complex geometries. This enables the method to model realistic
fracture shapes, on a pore-scale level, and predict the shape of the
fracture after acidizing. Results of carbonate
fracture dissolution with and without the thermal effects are presented. It is found that including thermal effects alters the predicted shape of the
fracture after acidizing.
Advisors/Committee Members: Nasr-El-Din, Hisham (advisor).
Subjects/Keywords: Fracture
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APA (6th Edition):
Lyons, J. (2013). A Novel Model for Fracture Acidizing with Important Thermal Effects. (Thesis). Texas Digital Library. Retrieved from http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66577
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Lyons, John. “A Novel Model for Fracture Acidizing with Important Thermal Effects.” 2013. Thesis, Texas Digital Library. Accessed March 04, 2021.
http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66577.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Lyons, John. “A Novel Model for Fracture Acidizing with Important Thermal Effects.” 2013. Web. 04 Mar 2021.
Vancouver:
Lyons J. A Novel Model for Fracture Acidizing with Important Thermal Effects. [Internet] [Thesis]. Texas Digital Library; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66577.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Lyons J. A Novel Model for Fracture Acidizing with Important Thermal Effects. [Thesis]. Texas Digital Library; 2013. Available from: http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66577
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
2.
Grantab, Rassin.
Computational Studies of Fracture in Micro- and Nano-Scale
Structures.
Degree: PhD, Solid Mechanics, 2012, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:297637/
► The electronics industry drives a great deal of research towards inventing methods for creating smaller devices. In order for the current trend of the diminishing…
(more)
▼ The electronics industry drives a great deal of
research towards inventing methods for creating smaller devices. In
order for the current trend of the diminishing size of electronic
devices - such as cell phones and laptops - to continue, two main
breakthroughs are necessary: firstly, the electronic components
themselves must become smaller without a loss of computing power;
and secondly, the batteries that store the energy for these devices
must also become smaller without a loss of capacity. Semiconductor
nanowires and graphene present promising solutions for making
smaller electronic circuits, while lithium-ion batteries are
currently the most space-efficient energy-storage device. In order
for nanowires, graphene, and lithium-ion batteries to gain
widespread use, both their performance and reliability are of
paramount importance. Despite the fact that these nano- and
micro-scale structures are not directly under mechanical loads,
their reliability is still largely dictated by mechanical failure
during use, and therefore must be well-understood. To this end, the
work presented herein describes detailed analyses of
fracture and
failure in these small-scale structures. At the nanoscale,
fracture
in faceted semiconductor nanowires and graphene sheets containing
grain boundaries has been studied using molecular dynamics
techniques. Interestingly, the results of the molecular dynamics
simulations of the nanowires can easily be explained using
continuum
fracture mechanics, while the results of the graphene
sheets with grain boundaries are in complete discord with continuum
theories and general intuition. In the case of the lithium-ion
batteries, finite element simulations of crack propagation in
electrodes have been used to understand how initial defects grow in
graphite and silicon electrode particles during battery charging
and use.
Advisors/Committee Members: Shenoy, Vivek (Director), Guduru, Pradeep (Reader), Sheldon, Brian (Reader).
Subjects/Keywords: fracture
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APA (6th Edition):
Grantab, R. (2012). Computational Studies of Fracture in Micro- and Nano-Scale
Structures. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:297637/
Chicago Manual of Style (16th Edition):
Grantab, Rassin. “Computational Studies of Fracture in Micro- and Nano-Scale
Structures.” 2012. Doctoral Dissertation, Brown University. Accessed March 04, 2021.
https://repository.library.brown.edu/studio/item/bdr:297637/.
MLA Handbook (7th Edition):
Grantab, Rassin. “Computational Studies of Fracture in Micro- and Nano-Scale
Structures.” 2012. Web. 04 Mar 2021.
Vancouver:
Grantab R. Computational Studies of Fracture in Micro- and Nano-Scale
Structures. [Internet] [Doctoral dissertation]. Brown University; 2012. [cited 2021 Mar 04].
Available from: https://repository.library.brown.edu/studio/item/bdr:297637/.
Council of Science Editors:
Grantab R. Computational Studies of Fracture in Micro- and Nano-Scale
Structures. [Doctoral Dissertation]. Brown University; 2012. Available from: https://repository.library.brown.edu/studio/item/bdr:297637/
3.
Olarnrithinun, Sutee.
Discrete Dislocation Modeling of Fracture/Fatigue.
Degree: PhD, Solid Mechanics, 2013, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:320484/
► The discrete dislocation (DD) plasticity is truly mechanism-based plasticity and well-suited for mesoscale modeling in metal. The effects of size-dependent plasticity and plastic dissipation emerge…
(more)
▼ The discrete dislocation (DD) plasticity is truly
mechanism-based plasticity and well-suited for mesoscale modeling
in metal. The effects of size-dependent plasticity and plastic
dissipation emerge naturally from this framework.
The micromechanics of
fracture is material dependent and
involves a broad range of length and time scales. The intermediate
situation between the cleavage crack growth and the plastic
dissipation involved in
fracture based on DD plasticity is focused
here.
Fracture crack growth is affected by dislocations: (i)
dislocation motion shields the crack tip and increases the
dissipation energy and (ii) the local stress concentration
associated with discrete dislocation in the vicinity of the crack
tip can reach atomic bond strength, causing the crack to grow.
In this work fatigue crack growth from small cracked particle
into single crystal is first investigated with a focus on the
effects of plastic confinement due to elastic particle, and elastic
modulus mismatch between the reinforcement and matrix phases.
The results show that fatigue crack growth from micron-scale
particles is strongly influenced by size effect of plasticity,
elastic mismatch, and the presence of particle to plastic flow.
However the yield stress of the matrix material and the
cohesive strength in the cohesive zone model are unrealistic due to
the limitations of the standard DD algorithm.
Also the computational cost and storage can be reduced by
using symmetric boundaries.
Therefore the new algorithm of discrete dislocation
plasticity to improve the computational efficiency and its
application in the short crack problem are presented here.
To study the role of plastic anisotropy on crack growth in a
single crystal, the standard DD formulation can be extended to
perform the effects of plastic dissipation and dislocation/crack
interaction on the basal cleavage in HCP-like material.
To do so, the concept of plastic flow controlled by a Peierls
stress is first implemented to the standard DD methodology. The
results show that the
fracture toughness is largely independent of
plastic anisotropy.
Interestingly, the
fracture toughnesses of both Peierls
stress-controlled flow material and obstacle-controlled flow
material are unified through the new Stress Gradient Plasticity
concept.
Advisors/Committee Members: Curtin, William (Director), Blume, Janet (Reader), Padture, Nitin (Reader).
Subjects/Keywords: Fracture
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APA (6th Edition):
Olarnrithinun, S. (2013). Discrete Dislocation Modeling of Fracture/Fatigue. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:320484/
Chicago Manual of Style (16th Edition):
Olarnrithinun, Sutee. “Discrete Dislocation Modeling of Fracture/Fatigue.” 2013. Doctoral Dissertation, Brown University. Accessed March 04, 2021.
https://repository.library.brown.edu/studio/item/bdr:320484/.
MLA Handbook (7th Edition):
Olarnrithinun, Sutee. “Discrete Dislocation Modeling of Fracture/Fatigue.” 2013. Web. 04 Mar 2021.
Vancouver:
Olarnrithinun S. Discrete Dislocation Modeling of Fracture/Fatigue. [Internet] [Doctoral dissertation]. Brown University; 2013. [cited 2021 Mar 04].
Available from: https://repository.library.brown.edu/studio/item/bdr:320484/.
Council of Science Editors:
Olarnrithinun S. Discrete Dislocation Modeling of Fracture/Fatigue. [Doctoral Dissertation]. Brown University; 2013. Available from: https://repository.library.brown.edu/studio/item/bdr:320484/
Wake Forest University
4.
PATALAK, JOHN.
Evaluation of Lower Extremity Injury Mitigation and Investigation of Thoracolumbar Loading of Restrained Occupants During Frontal Crashes.
Degree: 2017, Wake Forest University
URL: http://hdl.handle.net/10339/89875
Motor vehicle crashes (MVCs) of passenger vehicles are commonly cited and reported in published literature as a leading cause of death and injury. Similarly, in motorsports, on-track crashes are the leading cause of driver injury.
Subjects/Keywords: fracture
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APA (6th Edition):
PATALAK, J. (2017). Evaluation of Lower Extremity Injury Mitigation and Investigation of Thoracolumbar Loading of Restrained Occupants During Frontal Crashes. (Thesis). Wake Forest University. Retrieved from http://hdl.handle.net/10339/89875
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
PATALAK, JOHN. “Evaluation of Lower Extremity Injury Mitigation and Investigation of Thoracolumbar Loading of Restrained Occupants During Frontal Crashes.” 2017. Thesis, Wake Forest University. Accessed March 04, 2021.
http://hdl.handle.net/10339/89875.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
PATALAK, JOHN. “Evaluation of Lower Extremity Injury Mitigation and Investigation of Thoracolumbar Loading of Restrained Occupants During Frontal Crashes.” 2017. Web. 04 Mar 2021.
Vancouver:
PATALAK J. Evaluation of Lower Extremity Injury Mitigation and Investigation of Thoracolumbar Loading of Restrained Occupants During Frontal Crashes. [Internet] [Thesis]. Wake Forest University; 2017. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/10339/89875.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
PATALAK J. Evaluation of Lower Extremity Injury Mitigation and Investigation of Thoracolumbar Loading of Restrained Occupants During Frontal Crashes. [Thesis]. Wake Forest University; 2017. Available from: http://hdl.handle.net/10339/89875
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Oregon State University
5.
Semrick, Kalin.
Determining fracture toughness by orthogonal cutting of polyethylene and wood-polyethylene composites.
Degree: MS, Wood Science, 2012, Oregon State University
URL: http://hdl.handle.net/1957/30261
► The purpose of this thesis was to evaluate orthogonal cutting as a method to determine the fracture toughness of low and high density polyethylene and…
(more)
▼ The purpose of this thesis was to evaluate orthogonal cutting as a method to determine the
fracture toughness of low and high density polyethylene and wood plastic composites. A test fixture was developed to capture normal and tangential cutting forces at variable depth and rake angle. A tool interface method (TIM) is proposed to separate forces on both sides of the tool from the energy needed to propagate the crack. Also investigated were shear plane models of chip failure, which seek to measure toughness by modeling internal stresses in the chip. These results are compared to current methods of determining essential work of
fracture (EWF). It is found that cutting requires much less energy than current methods of EWF. Further work is suggested to better parameterize failure.
Advisors/Committee Members: Nairn, John (advisor), Kruzic, Jamie (committee member).
Subjects/Keywords: Fracture; Plastic-impregnated wood – Fracture
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APA (6th Edition):
Semrick, K. (2012). Determining fracture toughness by orthogonal cutting of polyethylene and wood-polyethylene composites. (Masters Thesis). Oregon State University. Retrieved from http://hdl.handle.net/1957/30261
Chicago Manual of Style (16th Edition):
Semrick, Kalin. “Determining fracture toughness by orthogonal cutting of polyethylene and wood-polyethylene composites.” 2012. Masters Thesis, Oregon State University. Accessed March 04, 2021.
http://hdl.handle.net/1957/30261.
MLA Handbook (7th Edition):
Semrick, Kalin. “Determining fracture toughness by orthogonal cutting of polyethylene and wood-polyethylene composites.” 2012. Web. 04 Mar 2021.
Vancouver:
Semrick K. Determining fracture toughness by orthogonal cutting of polyethylene and wood-polyethylene composites. [Internet] [Masters thesis]. Oregon State University; 2012. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1957/30261.
Council of Science Editors:
Semrick K. Determining fracture toughness by orthogonal cutting of polyethylene and wood-polyethylene composites. [Masters Thesis]. Oregon State University; 2012. Available from: http://hdl.handle.net/1957/30261
Texas A&M University
6.
Li, Jiawei.
Integration of Fracture Propagation Model and Reservoir Simulation Model for Analyzing the Impact of Fracture Complexity.
Degree: MS, Petroleum Engineering, 2018, Texas A&M University
URL: http://hdl.handle.net/1969.1/173661
► Simulation of the impact of hydraulic fracture geometry on well performance has become significantly important for unconventional reservoir development recently. In most literatures, simple bi-wing-fracture…
(more)
▼ Simulation of the impact of hydraulic
fracture geometry on well performance has become significantly important for unconventional reservoir development recently. In most literatures, simple bi-wing-
fracture pattern is assumed due to the difficulty and uncertainty in predicting the
fracture geometry. However, bi-wing-
fracture pattern does not agree with complex-
fracture geometry in the way they influence reservoir behaviors. In this study, an integration framework of
fracture propagation and reservoir simulation models has been developed to analyze the impact of complex-
fracture and simple bi-wing-
fracture pattern on well productivity and subsequent activities of enhancement hydrocarbon recovery.
First, an in-house
fracture-propagation model is used to predict the complex hydraulic
fracture geometry by considering elastic deformation of the rock and fluid flow. Then, the predicted
fracture geometry is automatically read and transferred to a reservoir simulator through the embedded discrete
fracture model (EDFM). In EDFM, the reservoir is discretized with structured gridding and additional grids are introduced for fractures. Each
fracture plane is embedded inside matrix grid and is discretized by cell boundaries. Through non-neighboring connections, the EDFM can properly handle complex
fracture geometries by modifying transmissibility.
The integrated model is applied to investigate the effect of complex
fracture networks in Eagle Ford reservoir. The complex-
fracture geometry is predicted by the
fracture propagation model and calibrated by diagnostic data. Then the
fracture parameters are processed with EDFM and transferred to numerical simulator. First, the history match results of different numerical cases with different complexity of
fracture networks are compared. The oil flow rates are used as input
iii
data and we history match the bottom-hole pressure, gas flow rate and water flow rate. Simulation results show that higher
fracture conductivity is required for bi-wing-
fracture case compared with complex-
fracture case to match the field data. Further, complex-
fracture network can better capture the pressure drop in transient state. Then, the effects of
fracture complexity on long term production and wettability alteration are investigated. The results confirms that complex
fracture networks does not agree with the simple bi-wing
fracture networks the way they influence reservoir behavior and wettability alteration. Additionally, the impact of natural fractures on the wettability alteration is investigated. The results indicate that the existence of natural fractures significantly amplifies the effect of wettability alteration and vice versa.
The EDFM in this paper efficiently transfers the
fracture propagation model results to a reservoir simulator, making it possible oil industry to effectively simulate the entire scenario from hydraulic fracturing to the production process. Moreover, this paper explains how different it is the way the complex-
fracture networks and simple-
fracture networks influence the reservoir…
Advisors/Committee Members: Wu, Kan (advisor), Duan, Benchun (committee member), Gildin, Eduardo (committee member).
Subjects/Keywords: Fracture propagation; Complex fracture geometry
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APA ·
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APA (6th Edition):
Li, J. (2018). Integration of Fracture Propagation Model and Reservoir Simulation Model for Analyzing the Impact of Fracture Complexity. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/173661
Chicago Manual of Style (16th Edition):
Li, Jiawei. “Integration of Fracture Propagation Model and Reservoir Simulation Model for Analyzing the Impact of Fracture Complexity.” 2018. Masters Thesis, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/173661.
MLA Handbook (7th Edition):
Li, Jiawei. “Integration of Fracture Propagation Model and Reservoir Simulation Model for Analyzing the Impact of Fracture Complexity.” 2018. Web. 04 Mar 2021.
Vancouver:
Li J. Integration of Fracture Propagation Model and Reservoir Simulation Model for Analyzing the Impact of Fracture Complexity. [Internet] [Masters thesis]. Texas A&M University; 2018. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/173661.
Council of Science Editors:
Li J. Integration of Fracture Propagation Model and Reservoir Simulation Model for Analyzing the Impact of Fracture Complexity. [Masters Thesis]. Texas A&M University; 2018. Available from: http://hdl.handle.net/1969.1/173661
University of Alberta
7.
Zhang, Lei.
Three-dimensional Numerical Models of Drilling Induced Core
Fractures.
Degree: MS, Department of Electrical and Computer
Engineering, 2011, University of Alberta
URL: https://era.library.ualberta.ca/files/p2676w188
► Drilling-induced fractures in borehole cores have distinct morphologies (e.g., petal, petal-centreline, saddle, and disk) and are produced under pure tensional stress, although most in-situ stresses…
(more)
▼ Drilling-induced fractures in borehole cores have
distinct morphologies (e.g., petal, petal-centreline, saddle, and
disk) and are produced under pure tensional stress, although most
in-situ stresses are compressive. 3D numerical models show that
tensile stress concentrations occur near the bottom of a vertical
borehole. A new algorithm is developed to trace 3D tensile
fractures for a range of crustal stress conditions. In a normal
fault regime, fractures change from petal/petal-centreline to
saddle to disk with increasing minimum horizontal stress (Sh). In a
strike-slip regime, saddle fractures occur, except where Sh is much
less than the vertical stress and petal centre-line fractures are
found. In a thrust fault regime, saddle and disk fractures occur at
low and high Sh, respectively. The results demonstrate that in-situ
stress is the dominant control on fracture morphology; variations
in Poisson’s ratio and core stub length primarily affect the
magnitude of tensile stress.
Subjects/Keywords: core fracture
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APA ·
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APA (6th Edition):
Zhang, L. (2011). Three-dimensional Numerical Models of Drilling Induced Core
Fractures. (Masters Thesis). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/p2676w188
Chicago Manual of Style (16th Edition):
Zhang, Lei. “Three-dimensional Numerical Models of Drilling Induced Core
Fractures.” 2011. Masters Thesis, University of Alberta. Accessed March 04, 2021.
https://era.library.ualberta.ca/files/p2676w188.
MLA Handbook (7th Edition):
Zhang, Lei. “Three-dimensional Numerical Models of Drilling Induced Core
Fractures.” 2011. Web. 04 Mar 2021.
Vancouver:
Zhang L. Three-dimensional Numerical Models of Drilling Induced Core
Fractures. [Internet] [Masters thesis]. University of Alberta; 2011. [cited 2021 Mar 04].
Available from: https://era.library.ualberta.ca/files/p2676w188.
Council of Science Editors:
Zhang L. Three-dimensional Numerical Models of Drilling Induced Core
Fractures. [Masters Thesis]. University of Alberta; 2011. Available from: https://era.library.ualberta.ca/files/p2676w188
8.
Shekhawat, Ashivni.
Fracture In Brittle Disordered Media.
Degree: PhD, Theoretical and Applied Mechanics, 2013, Cornell University
URL: http://hdl.handle.net/1813/34107
► This thesis consists of three main chapters, an introduction, and an appendix. The introduction (chapter 1) gives a general historical introduction to the problem of…
(more)
▼ This thesis consists of three main chapters, an introduction, and an appendix. The introduction (chapter 1) gives a general historical introduction to the problem of brittle
fracture in disordered media. Chapters 2 and 4 are concerned with various aspects of
fracture in disordered fuse networks. Chapter 2 investigates the asymptotic properties of
fracture strength distributions, and explores their relation with extreme value statistics. Chapter 4 deals with critical phenomena in brittle
fracture. This chapter introduces the concept of finite-sized criticality as a means to explain how
fracture can have mixed properties of abrupt and continuous phase transitions. Chapter 3 describes the collective dynamics at the non equilibrium metal insulator transition. The phenomenon of dielectric breakdown at the metal insulator transition shares several characteristics with
fracture, and provides a suitable build up to the development presented in chapter 4. The first three parts of the appendix provide an introduction to the various mathematical tools required in order to better appreciate the content of this thesis. Appendix A.1 discusses the basics of extreme value theory, while A.2 and A.3 provide a light introduction to linear elastic
fracture mechanics. Appendix A.4 summaries some results on crack propagation in graphene that are not sufficiently well developed to merit a chapter, and yet are developed enough to merit a mention.
Advisors/Committee Members: Sethna, James Patarasp (chair), Resnick, Sidney Ira (committee member), Phoenix, Stuart Leigh (committee member).
Subjects/Keywords: Fracture
…A Appendix
A.1 Extreme Value Statistics . . . . . . .
A.2 Linear Elastic Fracture… …insulator transition . . . . . . . . . .
36
38
40
4.1
4.2
4.3
Fracture in the fuse network at… …varying disorder . . . . . . . . . .
A scaling theory of fracture… …Phase diagram for brittle fracture in disordered media . . . . . .
45
50
53
Polar… …74
75
76
CHAPTER 1
INTRODUCTION
This is a thesis about fracture or how and why things…
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APA (6th Edition):
Shekhawat, A. (2013). Fracture In Brittle Disordered Media. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/34107
Chicago Manual of Style (16th Edition):
Shekhawat, Ashivni. “Fracture In Brittle Disordered Media.” 2013. Doctoral Dissertation, Cornell University. Accessed March 04, 2021.
http://hdl.handle.net/1813/34107.
MLA Handbook (7th Edition):
Shekhawat, Ashivni. “Fracture In Brittle Disordered Media.” 2013. Web. 04 Mar 2021.
Vancouver:
Shekhawat A. Fracture In Brittle Disordered Media. [Internet] [Doctoral dissertation]. Cornell University; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1813/34107.
Council of Science Editors:
Shekhawat A. Fracture In Brittle Disordered Media. [Doctoral Dissertation]. Cornell University; 2013. Available from: http://hdl.handle.net/1813/34107
Universidade Estadual de Campinas
9.
Gomes, Nilton Vivacqua, 1977-.
Comparison of nickel-titanium rotary systems longevity using a new mathematical analysis platform (M.A.P.E.R) = Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.): Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.).
Degree: 2012, Universidade Estadual de Campinas
URL: http://repositorio.unicamp.br/jspui/handle/REPOSIP/289065
► Abstract: The rotary instrumentation adds speed and quality to the endodontic treatment; however it is not routinely used. The endodontists are cautious on having the…
(more)
▼ Abstract: The rotary instrumentation adds speed and quality to the endodontic treatment; however it is not routinely used. The endodontists are cautious on having the mechanized instrumentation as a resource, due to the cost of constant file reposition that is necessary to avoid the fractures that the systems constantly suffer while using this process. Thus, it is important to develop sequences and/or systems that allow a greater safety margin regarding these fractures. The aim of the first part of this study is to make the comparison of 15 rotary instrumentation systems through a mathematical method, which uses the Microsoft Excel program, developed by author. The mathematical model - named "Mathematical Analysis Platform of Enlargement Rate" (M.A.P.E.R.) - was used to calculate the rate of enlargement, strength and shearing pressure exerted in each half millimeter of the instruments in each one of the tested systems, which aided the creation of a new sequence - named RS6 (Rotary with Safety using 6 files) - that follows the best stress distribution as possible; hence, the RS6 became a benchmark. In this platform, we inserted the data of the shape, sequence, penetration and torque of each instrument, so it was possible for us to calculate the stresses exerted on each of the data and, thereby, identify the ones that are most likely to
fracture. Then, to assess the longevity of the instruments using this new technique, 350 maxillary and mandibular molars with until 35? degrees of root canal curvatures were instrumented by 8 matches of this new RS6 sequence. The new developed sequence, RS6 with K3 files, presented the action of forces and shearing pressures reduced, and reached an average of 116.1 root canals instrumented until rupture, which corroborates with the values of the platform. Analyzing the results, we can conclude that the mathematical platform was able to simulate the forces and pressures involved in the functioning of each file, in all the sequences tested. In the second part of this study, we used an in vitro method on extracted human teeth. The new sequence was then compared to the other two previously used in the mathematical platform (ProTaper and ProDesign) in 200 molars, until the
fracture of all instruments in duplicate. The number of root canals instrumented by each file was recorded and compared to the information calculated by the platform. In most instances, the separation occurred near the point of highest concentration of forces in the instruments. Once again, the newly designed sequence, RS6, showed the best results when compared to the other two. With an average of 110.0 (a) root canals until
fracture, counter 78.5 (b) from the ProDesign and 46.6 (c) from the ProTaper (p <0.05). In conclusion, the sequence RS6 allowed the reuse of the instruments with great safety, avoiding their
fracture
Advisors/Committee Members: UNIVERSIDADE ESTADUAL DE CAMPINAS (CRUESP), Souza Filho, Francisco José de, 1950-2014 (advisor), Universidade Estadual de Campinas. Faculdade de Odontologia de Piracicaba (institution), Programa de Pós-Graduação em Clínica Odontológica (nameofprogram), Cortez, Douglas Giordani Negreiros (committee member), Oliveira, Daniel Pinto (committee member), Záia, Alexandre Augusto (committee member), Ferreira, Ricardo (committee member).
Subjects/Keywords: Fratura; Fracture
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APA (6th Edition):
Gomes, Nilton Vivacqua, 1. (2012). Comparison of nickel-titanium rotary systems longevity using a new mathematical analysis platform (M.A.P.E.R) = Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.): Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.). (Thesis). Universidade Estadual de Campinas. Retrieved from http://repositorio.unicamp.br/jspui/handle/REPOSIP/289065
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Gomes, Nilton Vivacqua, 1977-. “Comparison of nickel-titanium rotary systems longevity using a new mathematical analysis platform (M.A.P.E.R) = Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.): Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.).” 2012. Thesis, Universidade Estadual de Campinas. Accessed March 04, 2021.
http://repositorio.unicamp.br/jspui/handle/REPOSIP/289065.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Gomes, Nilton Vivacqua, 1977-. “Comparison of nickel-titanium rotary systems longevity using a new mathematical analysis platform (M.A.P.E.R) = Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.): Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.).” 2012. Web. 04 Mar 2021.
Vancouver:
Gomes, Nilton Vivacqua 1. Comparison of nickel-titanium rotary systems longevity using a new mathematical analysis platform (M.A.P.E.R) = Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.): Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.). [Internet] [Thesis]. Universidade Estadual de Campinas; 2012. [cited 2021 Mar 04].
Available from: http://repositorio.unicamp.br/jspui/handle/REPOSIP/289065.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Gomes, Nilton Vivacqua 1. Comparison of nickel-titanium rotary systems longevity using a new mathematical analysis platform (M.A.P.E.R) = Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.): Comparação da longevidade de sistemas rotatórios de níquel-titânio utilizando uma nova plataforma de análise matemática (M.A.P.E.R.). [Thesis]. Universidade Estadual de Campinas; 2012. Available from: http://repositorio.unicamp.br/jspui/handle/REPOSIP/289065
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
10.
Underwood, Jarrod.
Acid Fracture and Fracture Conductivity Study of Field Rock Samples.
Degree: 2013, Texas Digital Library
URL: http://hdl.handle.net/1969;
http://hdl.handle.net/2249.1/66584
► Acid fracturing is a well stimulation strategy designed to increase the productivity of a producing well. The parameters of acid fracturing and the effects of…
(more)
▼ Acid fracturing is a well stimulation strategy designed to increase the productivity of a producing well. The parameters of acid fracturing and the effects of acid interaction on specific rock samples can be studied experimentally. Acid injection data and
fracture conductivity measurements obtained in the research presented in this thesis yielded results that qualified and quantified the impact of a specific acid system on rock samples of varying acid solubility.
Six rock samples from a carbonate reservoir were labeled A through F to protect proprietary information included in this research. A 2% potassium chloride solution was used for the acid system and
fracture conductivity measurements to prevent clay swelling. Injection temperature, contact time, and injection rate were designed to simulate field treatment conditions. The effects of a chelating agent on
fracture conductivity were also studied.
Before and after images of the rock samples indicated that the effect of 15% hydrochloric acid on the samples was limited but correlated with the rock acid solubility. Samples E and F had a greater value of acid solubility and showed noticeable surface etching. Samples A, B, and C had lower values of acid solubility and did not show signs of surface etching. Sample D was of moderate acid solubility and showed minimal signs of surface etching.
Fracture conductivity did not correlate directly with acid solubility, but likely was a function of inherent matrix permeability based on leak-off measurements and
fracture conductivity measurements. Finally, the
fracture conductivity of Sample D increased after exposure to a chelating agent.
Commonly, acid
fracture experimental studies are carried out with outcrop rock samples. The samples have more homogenous properties and without hydrocarbon content. In this study, cores from downhole formation were used. The original condition was preserved as much as possible to simulate real field situations. However, using field rock samples does present challenges not generally associated with outcrop rock samples.
Based on the information gathered from the work presented in this thesis, conclusions were drawn concerning the effectiveness of a 15% hydrochloric acid treatment in this formation and the challenges of using field rock samples.
Advisors/Committee Members: Zhu, Ding (advisor).
Subjects/Keywords: Acid Fracture
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APA (6th Edition):
Underwood, J. (2013). Acid Fracture and Fracture Conductivity Study of Field Rock Samples. (Thesis). Texas Digital Library. Retrieved from http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66584
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Underwood, Jarrod. “Acid Fracture and Fracture Conductivity Study of Field Rock Samples.” 2013. Thesis, Texas Digital Library. Accessed March 04, 2021.
http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66584.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Underwood, Jarrod. “Acid Fracture and Fracture Conductivity Study of Field Rock Samples.” 2013. Web. 04 Mar 2021.
Vancouver:
Underwood J. Acid Fracture and Fracture Conductivity Study of Field Rock Samples. [Internet] [Thesis]. Texas Digital Library; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66584.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Underwood J. Acid Fracture and Fracture Conductivity Study of Field Rock Samples. [Thesis]. Texas Digital Library; 2013. Available from: http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66584
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
11.
Catoor, Dhiraj.
Fracture in Single and Bicrystals of Zinc: Experiments and
Computational Modeling.
Degree: PhD, Division of Engineering. Materials Science
Engineering, 2008, Brown University
URL: https://repository.library.brown.edu/studio/item/bdr:58/
► In polycrystalline materials where transgranular cleavage is the preferred fracture mode, the crystallographic misorientation of fracture planes across grain boundaries can provide resistance to crack…
(more)
▼ In polycrystalline materials where transgranular
cleavage is the preferred
fracture mode, the crystallographic
misorientation of
fracture planes across grain boundaries can
provide resistance to crack growth, though the details of its
contribution to
fracture resistance is not fully understood. Recent
studies on diverse structural materials such as steels, aluminum
alloys and intermetallics show a correlation between an increased
fracture resistance and the twist component of grain
misorientation; however the lack of control over the degree and
type of misorientation has precluded a systematic analysis of the
problem. In this dessertation, this phenomenon is investigated
through in situ crack propagation experiments across grain
boundaries of controlled twist misorientation in bicrystals of
zinc. The lack of comprehensive understanding of the
micromechanisms of
fracture in single crystals of zinc required in
situ experiments to be initially conducted to investigate crack
propagation on the basal planes. In single crystals, quasistatic
loading caused crack propagation in short bursts of dynamic crack
extension followed by periods of arrests. In situ observations
confirmed re-nucleation of micro-cracks on parallel basal planes
and failure of the linking ligaments and crack-growth resistance
due to pre-existing twins in the crack path. The crack growth
response, load-displacement behavior and
fracture surface
topography were all found to be dependent on the crack propagation
direction on the basal plane. Significant resistance to crack
propagation was observed in bicrystals at the grain boundaries
through extrinsic toughening mechanisms that come into play upon
crack stagnation at the boundary. Strong dependence of the load
displacement behavior and crack propagation resistance on the twist
angle was observed. Several accommodation mechanisms such as
twinning in the crack-wake, strain localization and slip band
blocking contribute to
fracture resistance and suppress crack
propagation across grain boundary at higher twist angles.
Three-dimensional finite element models incorporating crystal
plasticity are used to explain the micromechanisms of crack
propagation, orientation-dependent crack growth response and
fracture surface topography in single crystals, and qualitatively
capture several features of crack-grain boundary interaction in
bicrystals.
Advisors/Committee Members: Kumar, Sharvan (director), Bower, Allan (reader), Briant, Clyde (reader), Curtin, William (reader).
Subjects/Keywords: Fracture
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APA (6th Edition):
Catoor, D. (2008). Fracture in Single and Bicrystals of Zinc: Experiments and
Computational Modeling. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:58/
Chicago Manual of Style (16th Edition):
Catoor, Dhiraj. “Fracture in Single and Bicrystals of Zinc: Experiments and
Computational Modeling.” 2008. Doctoral Dissertation, Brown University. Accessed March 04, 2021.
https://repository.library.brown.edu/studio/item/bdr:58/.
MLA Handbook (7th Edition):
Catoor, Dhiraj. “Fracture in Single and Bicrystals of Zinc: Experiments and
Computational Modeling.” 2008. Web. 04 Mar 2021.
Vancouver:
Catoor D. Fracture in Single and Bicrystals of Zinc: Experiments and
Computational Modeling. [Internet] [Doctoral dissertation]. Brown University; 2008. [cited 2021 Mar 04].
Available from: https://repository.library.brown.edu/studio/item/bdr:58/.
Council of Science Editors:
Catoor D. Fracture in Single and Bicrystals of Zinc: Experiments and
Computational Modeling. [Doctoral Dissertation]. Brown University; 2008. Available from: https://repository.library.brown.edu/studio/item/bdr:58/
University of Otago
12.
Adsett, Luke.
Patterns and trends in facial fractures in New Zealand
.
Degree: 2011, University of Otago
URL: http://hdl.handle.net/10523/2024
► Intro: Fracture of the human facial skeleton is a common injury that places serious burden on society. Severe morbidity, mortality, facial disfigurement, loss of function…
(more)
▼ Intro:
Fracture of the human facial skeleton is a common injury that places serious burden on society. Severe morbidity, mortality, facial disfigurement, loss of function and financial cost are all associated with facial fractures (Kieser et al., 2002). In New Zealand (NZ), only two previous studies have looked at the aetiology, incidence, age, gender and ethnic distribution of facial fractures at a national level; the most recent was conducted in 1998. In addition, approximately 40% of facial fractures in NZ involve the consumption of alcohol (Adams et al., 2000; Buchanan et al., 2005; Lee and Antoun, 2009; Tong et al., 2010). The legal purchasing age of alcohol in NZ, was lowered from 20 years of age to 18 years of age in December 1999. To date, no research has investigated what influence lowering the legal purchasing age of alcohol has had on the trends and patterns of facial fractures.
Aims: To describe the aetiology, incidence, age, gender and ethnic distribution of facial fractures in NZ from 1999 to 2009. To review the patterns and trends of facial fractures occurring in NZ from 1999 to 2009 with those previously identified. To identify whether lowering the legal alcohol purchasing age has influenced facial fractures. To identity whether Māori still experience a disproportionate risk of facial fractures with respect to other NZ ethnic groups.
Materials and Methods: This was a retrospective study investigating data on facial fractures that occurred between 30th June 1999 and 1st July 2009. Data were gathered from the Ministry of Health (MOH) and the Accident Compensation Corporation of New Zealand (ACC). Patient demographic characteristics and the details of injury (including alcohol involvement) were analysed and described.
Results: Over the study period, the incidence of facial fractures was constant and a total of 26,637 were coded by the MOH. Most facial fractures (78%) occurred in males, giving a male-to-female ratio of 4:1. Comparison of data for the period 1979 to 1998 highlighted that peak injury rates, especially in males, coincide with the legal alcohol purchasing age at the time. Since 1998, more injuries have occurred in the younger NZ population, with peak injury rates shifting from 20 years to 18 years of age. Interpersonal violence (IPV) is the leading cause of facial fractures in NZ accounting for almost 40% of all fractures. In addition, the number of injuries attributed to IPV is increasing each year. Māori still continue to experience a disproportionate level of facial fractures, twice that of the NZ European population.
Conclusion: IPV is an increasing problem in NZ and contributes to a greater number of facial fractures each year. More measures are required to reduce the number of IPV-related injuries. Perhaps the most influential would be to return the legal alcohol purchasing age to 20 years. More is also required to reduce facial fractures in the high-risk groups of young adults, males, and Māori.
Advisors/Committee Members: Thomson, William Murray (advisor).
Subjects/Keywords: Fracture;
Facial
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APA (6th Edition):
Adsett, L. (2011). Patterns and trends in facial fractures in New Zealand
. (Doctoral Dissertation). University of Otago. Retrieved from http://hdl.handle.net/10523/2024
Chicago Manual of Style (16th Edition):
Adsett, Luke. “Patterns and trends in facial fractures in New Zealand
.” 2011. Doctoral Dissertation, University of Otago. Accessed March 04, 2021.
http://hdl.handle.net/10523/2024.
MLA Handbook (7th Edition):
Adsett, Luke. “Patterns and trends in facial fractures in New Zealand
.” 2011. Web. 04 Mar 2021.
Vancouver:
Adsett L. Patterns and trends in facial fractures in New Zealand
. [Internet] [Doctoral dissertation]. University of Otago; 2011. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/10523/2024.
Council of Science Editors:
Adsett L. Patterns and trends in facial fractures in New Zealand
. [Doctoral Dissertation]. University of Otago; 2011. Available from: http://hdl.handle.net/10523/2024
Oregon State University
13.
Addison, Dylan, A.
Time-Dependent Crack Growth Mechanisms in Alloy 617 at 800°C in Air.
Degree: MS, 2017, Oregon State University
URL: http://hdl.handle.net/1957/61609
► Time-dependent crack growth mechanisms in Alloy 617 at 800°C in air were studied using compact tension samples machined in the L-T direction, cracked at temperature…
(more)
▼ Time-dependent crack growth mechanisms in Alloy 617 at 800°C in air were studied using compact tension samples machined in the L-T direction, cracked at temperature using an induction furnace and servo-hydraulic load frame. The application of different loading waveforms, including triangular, hold time, and sustained loading, were studied with relation to relevant crack tip parameters in order to better understand the material’s viscoplastic response to crack growth mechanisms.
Fracture surfaces and crack tip profiles were examined to discover relevant relationships between transgranular cracking, void growth and coalescence, and the role of oxygen embrittlement. A transition from transgranular cracking to void coalescence was noted, and the mechanism mapped, both onto the results obtained in this work and the existing literature. Additionally, overload experiments aided in describing stress relaxation as the dominant transgranular mechanism governing crack growth below Kth, the sustained load crack growth threshold stress intensity factor, which is also reported herein.
Advisors/Committee Members: Kruzic, Jamie, J. (advisor), Bay, Brian, K. (committee member).
Subjects/Keywords: Fracture Mechanics
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APA (6th Edition):
Addison, Dylan, A. (2017). Time-Dependent Crack Growth Mechanisms in Alloy 617 at 800°C in Air. (Masters Thesis). Oregon State University. Retrieved from http://hdl.handle.net/1957/61609
Chicago Manual of Style (16th Edition):
Addison, Dylan, A. “Time-Dependent Crack Growth Mechanisms in Alloy 617 at 800°C in Air.” 2017. Masters Thesis, Oregon State University. Accessed March 04, 2021.
http://hdl.handle.net/1957/61609.
MLA Handbook (7th Edition):
Addison, Dylan, A. “Time-Dependent Crack Growth Mechanisms in Alloy 617 at 800°C in Air.” 2017. Web. 04 Mar 2021.
Vancouver:
Addison, Dylan A. Time-Dependent Crack Growth Mechanisms in Alloy 617 at 800°C in Air. [Internet] [Masters thesis]. Oregon State University; 2017. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1957/61609.
Council of Science Editors:
Addison, Dylan A. Time-Dependent Crack Growth Mechanisms in Alloy 617 at 800°C in Air. [Masters Thesis]. Oregon State University; 2017. Available from: http://hdl.handle.net/1957/61609
Louisiana State University
14.
Sprinkle, Saybl Beauton.
Biomechanical evaluation of medial and lateral approaches for experimentally created medial condylar fractures of the equine third metacarpal bone.
Degree: MS, Veterinary Medicine, 2011, Louisiana State University
URL: etd-07072011-192636
;
https://digitalcommons.lsu.edu/gradschool_theses/729
► Objective -To compare the compression produced in reduction of experimentally created medial condylar fractures using lag screw fixation with medial vs. lateral approach, and to…
(more)
▼ Objective -To compare the compression produced in reduction of experimentally created medial condylar fractures using lag screw fixation with medial vs. lateral approach, and to determine the maximum torque at screw failure. Materials and Methods- Twelve (12) pairs (left and right) 3rd metacarpal bones (MC3) were collected from adult (2-7 years) Thoroughbreds euthanized for reasons unrelated to orthopedic disease. Complete parasagittal medial condylar osteotomies were created at a measurement of 9, 13, and 21 mm axial to the epicondylar fossa on four pairs each of cadaveric MC3 bones resulting in fracture fragments measuring 8, 12, and 20 mm in thickness. For each pair of cadaveric MC3, a lateral or medial approach was randomly selected to repair the condylar fracture using a single 4.5 mm AO cortical screw. Each repair was tested for fracture plane compression and screw torque to failure. Results-There was no significant difference in compression between the medial and lateral approaches for the 8 or 12-mm fragment groups. There was significantly more compression generated in the lateral approach when compared to the medial approach for the 20-mm fragment group. Failure occurred at significantly lower torque in the 8-mm group. There was no significant difference between medial and lateral approach in torque to failure for the 12 and 20-mm groups. Conclusion-Based on this data we have concluded that there was no significant difference in torque to failure between a medial vs. lateral approach for the 12 mm fragments but there was a significant difference for the 8 mm fragments and that a lateral approach may be acceptable for the repair of medial condylar fractures in 12-mm or thicker fragments. The compression achieved by a medial approach was not significantly greater for the 8, 12 or 20-mm groups. Clinical Relevance- Based on our results the 20 mm size fragments reaches a higher compression at a faster rate when compared to the 8 and 12 mm size fragments. We recommend using caution when repairing medial condylar fractures with a lateral approach for fragment sizes measuring 8-mm thick. The smaller fragment torque to failure was low and not much higher than the insertional torque. Failure resulted from the screws stripping in the bone fragment. The screws in the thicker fragments (12 and 20 mm) engage more bone and have a higher torque to failure as a result.
Subjects/Keywords: Condylar fracture
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APA (6th Edition):
Sprinkle, S. B. (2011). Biomechanical evaluation of medial and lateral approaches for experimentally created medial condylar fractures of the equine third metacarpal bone. (Masters Thesis). Louisiana State University. Retrieved from etd-07072011-192636 ; https://digitalcommons.lsu.edu/gradschool_theses/729
Chicago Manual of Style (16th Edition):
Sprinkle, Saybl Beauton. “Biomechanical evaluation of medial and lateral approaches for experimentally created medial condylar fractures of the equine third metacarpal bone.” 2011. Masters Thesis, Louisiana State University. Accessed March 04, 2021.
etd-07072011-192636 ; https://digitalcommons.lsu.edu/gradschool_theses/729.
MLA Handbook (7th Edition):
Sprinkle, Saybl Beauton. “Biomechanical evaluation of medial and lateral approaches for experimentally created medial condylar fractures of the equine third metacarpal bone.” 2011. Web. 04 Mar 2021.
Vancouver:
Sprinkle SB. Biomechanical evaluation of medial and lateral approaches for experimentally created medial condylar fractures of the equine third metacarpal bone. [Internet] [Masters thesis]. Louisiana State University; 2011. [cited 2021 Mar 04].
Available from: etd-07072011-192636 ; https://digitalcommons.lsu.edu/gradschool_theses/729.
Council of Science Editors:
Sprinkle SB. Biomechanical evaluation of medial and lateral approaches for experimentally created medial condylar fractures of the equine third metacarpal bone. [Masters Thesis]. Louisiana State University; 2011. Available from: etd-07072011-192636 ; https://digitalcommons.lsu.edu/gradschool_theses/729
University of Texas – Austin
15.
-2987-0731.
Experimental study of the effect of stress and fluid sensitivity on propped and un-propped fracture conductivity in preserved reservoir shale.
Degree: MSin Engineering, Petroleum engineering, 2016, University of Texas – Austin
URL: http://hdl.handle.net/2152/39117
► A good amount of work has been done on analyzing the effect of stress and fluid sensitivity on fracture conductivity in sandstones. This thesis tries…
(more)
▼ A good amount of work has been done on analyzing the effect of stress and fluid sensitivity on
fracture conductivity in sandstones. This thesis tries to answer similar questions with regard to shale formations. Shales are very sensitive to aqueous fluids and their mechanical properties change when exposed to it. This mechanical property change in shale is mainly caused due to clay swelling. Some of the previous researchers working on shale fluid sensitivity failed to use preserved reservoir cores for their experiments and allowed them to dry out. This study has been conducted on preserved Utica and Eagle Ford core samples. Experiments were conducted to study the effect of effective stress on propped and un-propped
fracture conductivity. These experiments were conducted at reservoir temperature and pressure conditions to mimic field conditions. Different fluids were flowed through the
fracture to compare the effect of different fluids on
fracture conductivity. To prevent clay swelling various clay stabilizers are used in the field during drilling and fracturing operations. Experiments were conducted to test the effectiveness of different clay stabilizers in preventing
fracture conductivity reduction. Some of the clay stabilizers were more effective than others but all of them were unable to prevent
fracture conductivity reduction when
fracture was flowed with a high pH fluid.
Advisors/Committee Members: Sharma, Mukul M. (advisor), Daigle, Hugh C (advisor).
Subjects/Keywords: Fracture conductivity
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APA (6th Edition):
-2987-0731. (2016). Experimental study of the effect of stress and fluid sensitivity on propped and un-propped fracture conductivity in preserved reservoir shale. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/39117
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-2987-0731. “Experimental study of the effect of stress and fluid sensitivity on propped and un-propped fracture conductivity in preserved reservoir shale.” 2016. Masters Thesis, University of Texas – Austin. Accessed March 04, 2021.
http://hdl.handle.net/2152/39117.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-2987-0731. “Experimental study of the effect of stress and fluid sensitivity on propped and un-propped fracture conductivity in preserved reservoir shale.” 2016. Web. 04 Mar 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-2987-0731. Experimental study of the effect of stress and fluid sensitivity on propped and un-propped fracture conductivity in preserved reservoir shale. [Internet] [Masters thesis]. University of Texas – Austin; 2016. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2152/39117.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-2987-0731. Experimental study of the effect of stress and fluid sensitivity on propped and un-propped fracture conductivity in preserved reservoir shale. [Masters Thesis]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/39117
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
16.
Dana, Saumik P.
Simulation of growth of multiple interacting 3D cracks in hydraulic fractures driven by inviscid fluid.
Degree: MSin Engineering, Engineering Mechanics, 2014, University of Texas – Austin
URL: http://hdl.handle.net/2152/28538
► In this report, we develop a computational procedure to investigate propagation of 3D cracks in isotropic linearly elastic media in a 2D framework. We reduce…
(more)
▼ In this report, we develop a computational procedure to investigate propagation of 3D cracks in isotropic linearly elastic media in a 2D framework. We reduce the 3D weakly singular, weak-form traction integral equation to its 2D analog by introducing a constraint on crack profile in out-of-plane direction. Symmetric Galerkin boundary element method based on the obtained 2D weak-form traction integral equation is adopted to model these fractures. In particular, we consider multiple interacting cracks in unbounded domain
subject to internal pressure to model hydraulic
fracture.
Advisors/Committee Members: Mear, Mark E. (advisor).
Subjects/Keywords: Hydraulic fracture
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APA (6th Edition):
Dana, S. P. (2014). Simulation of growth of multiple interacting 3D cracks in hydraulic fractures driven by inviscid fluid. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/28538
Chicago Manual of Style (16th Edition):
Dana, Saumik P. “Simulation of growth of multiple interacting 3D cracks in hydraulic fractures driven by inviscid fluid.” 2014. Masters Thesis, University of Texas – Austin. Accessed March 04, 2021.
http://hdl.handle.net/2152/28538.
MLA Handbook (7th Edition):
Dana, Saumik P. “Simulation of growth of multiple interacting 3D cracks in hydraulic fractures driven by inviscid fluid.” 2014. Web. 04 Mar 2021.
Vancouver:
Dana SP. Simulation of growth of multiple interacting 3D cracks in hydraulic fractures driven by inviscid fluid. [Internet] [Masters thesis]. University of Texas – Austin; 2014. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2152/28538.
Council of Science Editors:
Dana SP. Simulation of growth of multiple interacting 3D cracks in hydraulic fractures driven by inviscid fluid. [Masters Thesis]. University of Texas – Austin; 2014. Available from: http://hdl.handle.net/2152/28538
Dalhousie University
17.
Allan, Andrew.
A Biomechanical Investigation of a Novel Implant for the
Stabilization of Distal Radius Fractures.
Degree: Master of Applied Science, Department of Biomedical Engineering, 2012, Dalhousie University
URL: http://hdl.handle.net/10222/15396
► Distal radius fractures are the single most common type of fracture suffered among the adult population. Presently, clinical decision making regarding optimal treatment is inconclusive.…
(more)
▼ Distal radius fractures are the single most common
type of
fracture suffered among the adult population. Presently,
clinical decision making regarding optimal treatment is
inconclusive. The goal of this thesis was to design, develop, and
biomechanically test a novel implant for the stabilization of
distal radius fractures. The novel implant is intended to provide a
minimally invasive, low cost alternative to locked volar plates,
while still permitting an earlier return to function. The implant
consists of an angled bar with a sharp cutting edge and is inserted
using a minimally invasive approach through the radial styloid.
Surgical instrumentation was designed to facilitate the procedure
in a controlled manner. To determine whether the implant would be
capable of providing an early return to function, biomechanical
tests were conducted both experimentally and numerically.
Biomechanical testing showed that mechanical fixation with the
novel implant does not support and early return to
function.
Advisors/Committee Members: Dr. Darrel Doman (external-examiner), Dr. Sarah Wells (graduate-coordinator), Dr. Janie Astephen-Wilson (thesis-reader), Dr. Mark Filiaggi (thesis-reader), Dr. Michael Dunbar (thesis-supervisor), Not Applicable (ethics-approval), Not Applicable (manuscripts), Not Applicable (copyright-release).
Subjects/Keywords: Biomechanical, Distal Radius, Fracture Fixation; Fracture
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APA (6th Edition):
Allan, A. (2012). A Biomechanical Investigation of a Novel Implant for the
Stabilization of Distal Radius Fractures. (Masters Thesis). Dalhousie University. Retrieved from http://hdl.handle.net/10222/15396
Chicago Manual of Style (16th Edition):
Allan, Andrew. “A Biomechanical Investigation of a Novel Implant for the
Stabilization of Distal Radius Fractures.” 2012. Masters Thesis, Dalhousie University. Accessed March 04, 2021.
http://hdl.handle.net/10222/15396.
MLA Handbook (7th Edition):
Allan, Andrew. “A Biomechanical Investigation of a Novel Implant for the
Stabilization of Distal Radius Fractures.” 2012. Web. 04 Mar 2021.
Vancouver:
Allan A. A Biomechanical Investigation of a Novel Implant for the
Stabilization of Distal Radius Fractures. [Internet] [Masters thesis]. Dalhousie University; 2012. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/10222/15396.
Council of Science Editors:
Allan A. A Biomechanical Investigation of a Novel Implant for the
Stabilization of Distal Radius Fractures. [Masters Thesis]. Dalhousie University; 2012. Available from: http://hdl.handle.net/10222/15396
Texas A&M University
18.
Oeth, Cassandra V.
Three-dimensional Modeling of Acid Transport and Etching in a Fracture.
Degree: PhD, Petroleum Engineering, 2013, Texas A&M University
URL: http://hdl.handle.net/1969.1/151892
► Acid fracture stimulation generates higher well production but requires engineering design for treatment optimization. To quantify the cost and benefit of a particular acid fracture…
(more)
▼ Acid
fracture stimulation generates higher well production but requires engineering design for treatment optimization. To quantify the cost and benefit of a particular acid
fracture treatment an engineer must predict the resulting fracture’s conductivity, which is based on the etched width created by the injected acid. Etching occurs along the
fracture surface but is based on acid flowing through the
fracture, so an evaluation tool should describe three-dimensional physics and chemistry. Current practice is to estimate conductivity utilizing two-dimensional models. Unfortunately, these models necessarily assume how acid is distributed in the
fracture and often misrepresent the amount of acid etching upon which the conductivity is based.
A fully three-dimensional modeling tool to evaluate and predict acid
fracture performance across the wide range of carbonate field properties has been developed. The model simulates acid transport and
fracture face dissolution. The acid transport model includes the solution of the three-dimensional velocity and pressure fields, the non-Newtonian characteristics of most acid fracturing fluids, and diffusion of acid toward the
fracture surface. The model numerically solves the equations describing the three-dimensional acid transport and reaction within a
fracture to yield the etched width created by acid along the
fracture. The conductivity is calculated with the simulator derived acid-etched width, using correlations recently developed that reflect the small scale heterogeneity of carbonate rock as it creates etching along the
fracture surface.
The performance of an acid
fracture treatment is quantified with conductivity, which is strongly dependent on the etched width created by the acid. This robust new tool more accurately models the impact of design decisions on the acid-etched width and provides a rational path for treatment optimization. Cases typical of industry practice are presented that demonstrate the model capabilities.
Advisors/Committee Members: Hill, Alfred D (advisor), Zhu, Ding (committee member), Gildin, Eduardo (committee member), Handler, Robert A (committee member).
Subjects/Keywords: acid fracturing; fracture acidizing; fracture simulation
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APA (6th Edition):
Oeth, C. V. (2013). Three-dimensional Modeling of Acid Transport and Etching in a Fracture. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/151892
Chicago Manual of Style (16th Edition):
Oeth, Cassandra V. “Three-dimensional Modeling of Acid Transport and Etching in a Fracture.” 2013. Doctoral Dissertation, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/151892.
MLA Handbook (7th Edition):
Oeth, Cassandra V. “Three-dimensional Modeling of Acid Transport and Etching in a Fracture.” 2013. Web. 04 Mar 2021.
Vancouver:
Oeth CV. Three-dimensional Modeling of Acid Transport and Etching in a Fracture. [Internet] [Doctoral dissertation]. Texas A&M University; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/151892.
Council of Science Editors:
Oeth CV. Three-dimensional Modeling of Acid Transport and Etching in a Fracture. [Doctoral Dissertation]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/151892
Hong Kong University of Science and Technology
19.
Xie, Tao.
Effect of electrostatic tractions on the fracture behavior of a dielectric/piezoelectric material under mechanical and/or electric loading.
Degree: 2013, Hong Kong University of Science and Technology
URL: http://repository.ust.hk/ir/Record/1783.1-62370
;
https://doi.org/10.14711/thesis-b1255097
;
http://repository.ust.hk/ir/bitstream/1783.1-62370/1/th_redirect.html
► The effect of electrostatic tractions on the fracture behavior of a dielectric material under mechanical and/or electric loading is analyzed first by studying a pre-cracked…
(more)
▼ The effect of electrostatic tractions on the fracture behavior of a dielectric material under mechanical and/or electric loading is analyzed first by studying a pre-cracked parallel-plate capacitor and illustrated by plots. The research is then extended into the case of piezoelectric materials considering the anisotropic material properties and the piezoelectric effect. The results are illustrated by plots based on a specific lead zirconate titanate (PZT-5H) sample, and also for another piezoelectric material with even higher dielectric/piezoelectric constants. The results are presented in terms of electrostatic tractions, crack opening/closing, and energy release rate. For dielectric materials, electrostatic tractions on the electrodes compress the material in front of the crack tip and stretch the material behind the crack tip, having the tendency to close the crack. Mechanical load is the driving force to propagate the crack, while applied electric field retards crack propagation due to the electrostatic tractions. As a direct consequence, the fracture criterion is composed of two parts: the energy release rate must exceed a critical value and the mechanical load must be higher than the critical value for crack opening. The investigation into piezoelectric materials indicates that influence of electrostatic tractions depends on the direction of applied electric field due to the piezoelectric effect. Under a positive electric field (aligned with the poling direction), the electrostatic tractions stretch the material behind the crack tip and have the tendency to close the crack. While under a negative electric field (opposite to the poling direction), the electrostatic tractions compress the material behind the crack tip and promotes crack opening process. Mechanical load is always the driving force to propagate the crack, while the effect of electric loading on the crack propagation due to the electrostatic tractions depends on applied electric field direction. The fracture criterion is composed of two parts: the energy release rate must exceed a critical value and the mechanical load must be higher than the critical value for crack opening. Special attention has to be paid to the loading condition under negative electric field due to its contribution to assisting in the crack opening process.
Subjects/Keywords: Piezoelectric materials
; Fracture
; Dielectrics
; Fracture mechanics
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APA ·
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APA (6th Edition):
Xie, T. (2013). Effect of electrostatic tractions on the fracture behavior of a dielectric/piezoelectric material under mechanical and/or electric loading. (Thesis). Hong Kong University of Science and Technology. Retrieved from http://repository.ust.hk/ir/Record/1783.1-62370 ; https://doi.org/10.14711/thesis-b1255097 ; http://repository.ust.hk/ir/bitstream/1783.1-62370/1/th_redirect.html
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Xie, Tao. “Effect of electrostatic tractions on the fracture behavior of a dielectric/piezoelectric material under mechanical and/or electric loading.” 2013. Thesis, Hong Kong University of Science and Technology. Accessed March 04, 2021.
http://repository.ust.hk/ir/Record/1783.1-62370 ; https://doi.org/10.14711/thesis-b1255097 ; http://repository.ust.hk/ir/bitstream/1783.1-62370/1/th_redirect.html.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Xie, Tao. “Effect of electrostatic tractions on the fracture behavior of a dielectric/piezoelectric material under mechanical and/or electric loading.” 2013. Web. 04 Mar 2021.
Vancouver:
Xie T. Effect of electrostatic tractions on the fracture behavior of a dielectric/piezoelectric material under mechanical and/or electric loading. [Internet] [Thesis]. Hong Kong University of Science and Technology; 2013. [cited 2021 Mar 04].
Available from: http://repository.ust.hk/ir/Record/1783.1-62370 ; https://doi.org/10.14711/thesis-b1255097 ; http://repository.ust.hk/ir/bitstream/1783.1-62370/1/th_redirect.html.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Xie T. Effect of electrostatic tractions on the fracture behavior of a dielectric/piezoelectric material under mechanical and/or electric loading. [Thesis]. Hong Kong University of Science and Technology; 2013. Available from: http://repository.ust.hk/ir/Record/1783.1-62370 ; https://doi.org/10.14711/thesis-b1255097 ; http://repository.ust.hk/ir/bitstream/1783.1-62370/1/th_redirect.html
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Hong Kong University of Science and Technology
20.
Chen, E.
Study on concrete strength under uniaxial and biaxial loadings from the view of fracture mechanics.
Degree: 2011, Hong Kong University of Science and Technology
URL: http://repository.ust.hk/ir/Record/1783.1-7386
;
https://doi.org/10.14711/thesis-b1154860
;
http://repository.ust.hk/ir/bitstream/1783.1-7386/1/th_redirect.html
► Biaxial compression tests on cubic concrete specimens were performed on a newly designed triaxial machine. Specially designed steel brush platens were adopted in biaxial experiments…
(more)
▼ Biaxial compression tests on cubic concrete specimens were performed on a newly designed triaxial machine. Specially designed steel brush platens were adopted in biaxial experiments to reduce the end friction in order to obtain real uniform compression state in the specimens. Concrete with different maximum aggregate sizes were tested for their biaxial compressive strength, with fracture energy and characteristic length examined at the same time. It was found that the biaxial compressive strength of concrete was intrinsically dependent on the fracture energy and characteristic length rather than the uniaxial strength. Therefore, by introducing the fracture parameters, a trend of biaxial failure envelope can be more accurately described than previous research in which the uniaxial strength was always taken as the basis for deriving the envelope. This finding may provide a more accurate design criterion based on fracture parameters in multiaxial problems. On the other hand, numerical simulation of concrete behavior under uniaxial tension, uniaxial compression and combined compression-tension was carried out based on a proposed local softening model by the nonlinear finite element software ATENA. Pure mode I crack was assumed under uniaxial tension and the equivalent wing crack system was employed for uniaxial compression and biaxial compression-tension. The local softening behavior was simulated by means of the interface material model in ATENA. The relationships among the uniaxial compressive strength, tensile strength and the fracture energy under tension were well reproduced compared with the empirical relations. This implies that the local softening law can be viewed as the linkage of these macroscopic properties. Numerical biaxial compressive-tensile strengths based on the local softening model also showed good agreement with available experimental results. Therefore, non-linear fracture mechanics with the local softening law at the sub-macro-scale seems to be suitable for analyzing concrete behaviors at the macro-scale.
Subjects/Keywords: Concrete – Fracture – Mathematical models
; Fracture mechanics
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APA (6th Edition):
Chen, E. (2011). Study on concrete strength under uniaxial and biaxial loadings from the view of fracture mechanics. (Thesis). Hong Kong University of Science and Technology. Retrieved from http://repository.ust.hk/ir/Record/1783.1-7386 ; https://doi.org/10.14711/thesis-b1154860 ; http://repository.ust.hk/ir/bitstream/1783.1-7386/1/th_redirect.html
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Chen, E. “Study on concrete strength under uniaxial and biaxial loadings from the view of fracture mechanics.” 2011. Thesis, Hong Kong University of Science and Technology. Accessed March 04, 2021.
http://repository.ust.hk/ir/Record/1783.1-7386 ; https://doi.org/10.14711/thesis-b1154860 ; http://repository.ust.hk/ir/bitstream/1783.1-7386/1/th_redirect.html.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Chen, E. “Study on concrete strength under uniaxial and biaxial loadings from the view of fracture mechanics.” 2011. Web. 04 Mar 2021.
Vancouver:
Chen E. Study on concrete strength under uniaxial and biaxial loadings from the view of fracture mechanics. [Internet] [Thesis]. Hong Kong University of Science and Technology; 2011. [cited 2021 Mar 04].
Available from: http://repository.ust.hk/ir/Record/1783.1-7386 ; https://doi.org/10.14711/thesis-b1154860 ; http://repository.ust.hk/ir/bitstream/1783.1-7386/1/th_redirect.html.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Chen E. Study on concrete strength under uniaxial and biaxial loadings from the view of fracture mechanics. [Thesis]. Hong Kong University of Science and Technology; 2011. Available from: http://repository.ust.hk/ir/Record/1783.1-7386 ; https://doi.org/10.14711/thesis-b1154860 ; http://repository.ust.hk/ir/bitstream/1783.1-7386/1/th_redirect.html
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
21.
Lesaine, Arnaud.
Structural and mechanical properties of dried colloidal silica layers : Propriétés mécaniques et de structure de films formés par évaporation de suspensions colloïdales.
Degree: Docteur es, Mécanique des matériaux, 2018, Université Paris-Saclay (ComUE)
URL: http://www.theses.fr/2018SACLS597
► Le séchage d’une suspension colloïdale produit une couche solide plus ou moins poreuse. Ce processus intervient dans de nombreuses applications, telles que le procédé sol-gel…
(more)
▼ Le séchage d’une suspension colloïdale produit une couche solide plus ou moins poreuse. Ce processus intervient dans de nombreuses applications, telles que le procédé sol-gel ou la fabrication de laques et de peintures. Durant le séchage, l’évaporation du solvant entraîne la rétraction du matériau ; des contraintes importantes peuvent alors apparaître dans les couches colloïdales, les rendant susceptibles de se fracturer. Il est ainsi crucial de comprendre l’influence de paramètres de contrôle tels que la vitesse de séchage, l’épaisseur de la couche ou la taille de particule sur les propriétés mécaniques et de structure du matériau final. Dans cette thèse, nous avons utilisé des suspensions de Ludox (silice colloïdale) comme système modèle afin d’étudier l’effet de la vitesse de séchage sur les propriétés du matériau solide obtenu. Dans une première partie, nous avons mis en œuvre des mesures de porosité, ainsi que de microscopie à force atomique et de diffraction de rayons X, afin de caractériser l’effet de la vitesse de séchage sur les propriétés de structure des couches sèches. Nous avons mis en évidence l’importance de la polydispersité des suspensions initiales, ainsi que des phénomènes d’agrégation de particules, sur la structure et la compacité du matériau obtenu. Dans une deuxième partie, des mesures de constantes élastiques par propagation d’ultrasons nous ont permis de déterminer l’élasticité tensorielle (i.e. le module de compressibilité et celui de cisaillement) des couches colloïdales. Ces modules élastiques dépendent de la porosité du matériau ainsi que de la taille des particules de silice. Les données expérimentales ont été comparées aux prédictions de deux schémas d’homogénéisation (Mori-Tanaka et auto-cohérent), ainsi qu’au modèle de Kendall pour le module d’Young, qui prend en considération une énergie d’adhésion entre les particules. Enfin, nous avons déterminé la résistance à la fracture des couches colloïdales à l’aide de tests d’indentation Vickers. Cette résistance à la fracture, mesurée à la fin du séchage, est mise en relation avec la vitesse d’évaporation, la porosité du matériau, ainsi que la densité de fractures observées pendant le processus d’évaporation du solvant.
Drying a colloidal suspension results in the formation of a more or less porous solid layer. This procedure is central to many applications such as sol-gel processes, the design of paints and lacquers... As the solvent evaporation induces shrinkage of the material, large stresses can develop in these layers, making them prone to fracture. A crucial challenge is thus to understand the role of the control parameters, such as drying rate, film thickness and particle size, on the structural and mechanical properties of the final layer. In this thesis work, Ludox (colloidal silica) was used as a model system to study the effect of the drying rate on the structural and mechanical properties of the resultant solid. The effect of the drying rate on the structural properties of the dry layers was studied using porosity…
Advisors/Committee Members: Lazarus, Véronique (thesis director), Rountree, Cindy (thesis director).
Subjects/Keywords: Colloïdes; Séchage; Fracture; Colloids; Drying; Fracture
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APA (6th Edition):
Lesaine, A. (2018). Structural and mechanical properties of dried colloidal silica layers : Propriétés mécaniques et de structure de films formés par évaporation de suspensions colloïdales. (Doctoral Dissertation). Université Paris-Saclay (ComUE). Retrieved from http://www.theses.fr/2018SACLS597
Chicago Manual of Style (16th Edition):
Lesaine, Arnaud. “Structural and mechanical properties of dried colloidal silica layers : Propriétés mécaniques et de structure de films formés par évaporation de suspensions colloïdales.” 2018. Doctoral Dissertation, Université Paris-Saclay (ComUE). Accessed March 04, 2021.
http://www.theses.fr/2018SACLS597.
MLA Handbook (7th Edition):
Lesaine, Arnaud. “Structural and mechanical properties of dried colloidal silica layers : Propriétés mécaniques et de structure de films formés par évaporation de suspensions colloïdales.” 2018. Web. 04 Mar 2021.
Vancouver:
Lesaine A. Structural and mechanical properties of dried colloidal silica layers : Propriétés mécaniques et de structure de films formés par évaporation de suspensions colloïdales. [Internet] [Doctoral dissertation]. Université Paris-Saclay (ComUE); 2018. [cited 2021 Mar 04].
Available from: http://www.theses.fr/2018SACLS597.
Council of Science Editors:
Lesaine A. Structural and mechanical properties of dried colloidal silica layers : Propriétés mécaniques et de structure de films formés par évaporation de suspensions colloïdales. [Doctoral Dissertation]. Université Paris-Saclay (ComUE); 2018. Available from: http://www.theses.fr/2018SACLS597
Clemson University
22.
Rogers, Margeaux.
Biomechanical Testing of Salter-Harris Fractures Type I and II in the Distal Femur and Proximal Tibia.
Degree: MS, Bioengineering, 2013, Clemson University
URL: https://tigerprints.clemson.edu/all_theses/1675
► Salter-Harris fractures of the proximal tibia and distal femur are common in pediatric patients that present to orthopedic surgeons. Salter-Harris type I fractures are…
(more)
▼ Salter-Harris fractures of the proximal tibia and distal femur are common in pediatric patients that present to orthopedic surgeons. Salter-Harris type I fractures are characterized by breaks that extend only through the physis while Salter-Harris II fractures are the most common, accounting for 85% of Salter-Harris fractures, and extend past the growth plate, exiting through the metaphyseal bone1. Fixation of these
fracture types can be accomplished using a variety of methods including the use of Kirschner wires, cannulated screws, and a combination of both materials. Stability of
fracture fixation is of utmost importance as persistent motion at the
fracture margin leads to deformity2. Other complications resulting from unsuccessful
fracture treatment include knee instability, premature physeal closure, and leg shortening causing the patient to experience a higher physiological load1,3. The purpose of this study is to analyze the biomechanical efficacy of common fixation methods used to stabilize Salter-Harris I and II
fracture patterns in both the proximal tibia and distal femur. Rotational stiffness will be used as the primary gauge of efficacy and is tested in flexion and extension, varus and valgus rotation, and internal and external rotation. Comparison of stiffness will be used to determine the optimal fixation method specific to each bone and
fracture pattern. This study utilized 39 tibia and 36 femur 4th generation synthetic bones, fractured and fixated to model Salter-Harris type I and II fractures and common fixation methods. Fixation methods used employed 6.5mm cannulated screws, 4.5mm cannulated screws, 2mm smooth k-wires, and 2mm threaded k-wires. Cyclic displacement tests were performed on a materials testing machine which recorded the torque required to reach an angulation of ±5¡ for 10 cycles. Statistical analysis was performed to compare construct stiffness and differences between groups using analysis of variance. Results show superior stability achieved through the use of threaded k-wires for both femoral and tibial Salter-Harris type I
fracture fixation. The optimal femoral Salter-Harris type II fixation method utilized two oblique screws. Methods consisting of a combination of screws and k-wires resulted in the greatest rotational stiffness for tibial Salter-Harris type II fractures. Improvements in fixation methods should be considered to enhance internal and external rotational stiffness for all
fracture types.
Advisors/Committee Members: DesJardins, John D, LaBerge , Martine, Nagatomi , Jiro.
Subjects/Keywords: biomechanics; fracture fixation; physeal fracture; Biomechanics
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APA (6th Edition):
Rogers, M. (2013). Biomechanical Testing of Salter-Harris Fractures Type I and II in the Distal Femur and Proximal Tibia. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1675
Chicago Manual of Style (16th Edition):
Rogers, Margeaux. “Biomechanical Testing of Salter-Harris Fractures Type I and II in the Distal Femur and Proximal Tibia.” 2013. Masters Thesis, Clemson University. Accessed March 04, 2021.
https://tigerprints.clemson.edu/all_theses/1675.
MLA Handbook (7th Edition):
Rogers, Margeaux. “Biomechanical Testing of Salter-Harris Fractures Type I and II in the Distal Femur and Proximal Tibia.” 2013. Web. 04 Mar 2021.
Vancouver:
Rogers M. Biomechanical Testing of Salter-Harris Fractures Type I and II in the Distal Femur and Proximal Tibia. [Internet] [Masters thesis]. Clemson University; 2013. [cited 2021 Mar 04].
Available from: https://tigerprints.clemson.edu/all_theses/1675.
Council of Science Editors:
Rogers M. Biomechanical Testing of Salter-Harris Fractures Type I and II in the Distal Femur and Proximal Tibia. [Masters Thesis]. Clemson University; 2013. Available from: https://tigerprints.clemson.edu/all_theses/1675
University of Texas – Austin
23.
Alotaibi, Talal Eid.
Applications of phase-field modeling in hydraulic fracture.
Degree: PhD, Engineering Mechanics, 2020, University of Texas – Austin
URL: http://dx.doi.org/10.26153/tsw/8157
► Understanding the mechanisms behind the nucleation and propagation of cracks is of considerable interest in engineering application and design decisions. In many applications in the…
(more)
▼ Understanding the mechanisms behind the nucleation and propagation of cracks is of considerable interest in engineering application and design decisions. In many applications in the oil industry, complicated
fracture geometries and propagation behaviors are encountered. As a result, the development of modeling approaches that can capture the physics of non-planar crack evolution while being computationally tractable is a critical challenge. The phase-field approach to
fracture has been shown to be a powerful tool for simulating very complex
fracture topologies, including the turning, splitting, and merging of cracks. In contrast to
fracture models that explicitly track the crack surfaces, crack propagation and the evolution thereof arise out of the solution to a partial differential equation governing the evolution of a phase-field damage parameter. As such, the crack growth emerges naturally from solving the set of coupled differential equations linking the phase-field to other field quantities that can drive the
fracture process. In the present model, the physics of flow through porous media and cracks is coupled with the mechanics of
fracture. Darcy-type flow is modeled in the intact porous medium, which transitions to a Stokes-type flow regime within open cracks. This phase-field model is implemented to gain insights into the propagation behavior of fluid-injected cracks.
One outstanding issue with phase-field
fracture models is the decomposition of the strain energy required to ensure that compressive stress states do not cause crack propagation and damage evolution. In the present study, the proper representation of the strain energy function to reflect this
fracture phenomenon is examined. The strain energy is constructed in terms of principle strains in such a way that it has two parts; the tensile and the compressive. A degradation function only applies to the tensile part enforcing that the crack is driven only by that part of the strain energy. We investigated the split operator proposed by Miehe et al. [1], and then proposed a split approach based on masonry-like material behavior [2, 3]. We have found that when using Miehe’s form for the strain energy function, cracks can propagate under compressive stresses. In contrast, the approach based on a masonry-like materials constitutive model we proposed ensures that cracks do not grow under compressive stresses.
To demonstrate the capabilities of phase-field modeling for fluid-driven fractures, four general types of problems are simulated: 1) interactions of fluid-driven, natural, and proppant-filled cracks, 2) crack growth through different material layers, 3) fluid-driven crack growth under the influence of in-situ far-field stresses, and 4) crack interactions with inclusions. The simulations illustrate the capabilities of the phase-field model for capturing interesting and complex crack growth phenomena.
To understand how fluid-driven cracks interact with inclusions, AlTammar et al. [4] performed experiments. Three tests with tough inclusions were…
Advisors/Committee Members: Landis, Chad M. (advisor), Sharma, Mukul M (committee member), Mear, Mark E (committee member), Ravi-Chandar, Krishnaswa (committee member), Foster, John T (committee member).
Subjects/Keywords: Phase-field modeling; Hydraulic fracture; Fracture mechanics
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APA (6th Edition):
Alotaibi, T. E. (2020). Applications of phase-field modeling in hydraulic fracture. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/8157
Chicago Manual of Style (16th Edition):
Alotaibi, Talal Eid. “Applications of phase-field modeling in hydraulic fracture.” 2020. Doctoral Dissertation, University of Texas – Austin. Accessed March 04, 2021.
http://dx.doi.org/10.26153/tsw/8157.
MLA Handbook (7th Edition):
Alotaibi, Talal Eid. “Applications of phase-field modeling in hydraulic fracture.” 2020. Web. 04 Mar 2021.
Vancouver:
Alotaibi TE. Applications of phase-field modeling in hydraulic fracture. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2020. [cited 2021 Mar 04].
Available from: http://dx.doi.org/10.26153/tsw/8157.
Council of Science Editors:
Alotaibi TE. Applications of phase-field modeling in hydraulic fracture. [Doctoral Dissertation]. University of Texas – Austin; 2020. Available from: http://dx.doi.org/10.26153/tsw/8157
University of Texas – Austin
24.
-0908-0089.
Phase-field modeling of fracture for multiphysics problems.
Degree: PhD, Engineering mechanics, 2016, University of Texas – Austin
URL: http://hdl.handle.net/2152/46492
► Several recent works have demonstrated that phase-field methods for modeling fracture are capable of yielding complex crack evolution patterns in materials. This includes the nucleation,…
(more)
▼ Several recent works have demonstrated that phase-field methods for modeling
fracture are capable of yielding complex crack evolution patterns in materials. This includes the nucleation, turning, branching, and merging of cracks
subject to a variety of quasi-static and dynamic loadings. What follows will demonstrate how phase-field methods for
fracture can be applied to problems involving materials
subject to electromechanical coupling and the problem of hydraulic
fracture. Brittle
fracture is a major concern in piezoelectric ceramics.
Fracture propagation in these materials is heavily influenced by the mechanical and electrical fields within the material as well as the boundary conditions on the crack surfaces. These conditions can lead to complex multi-modal crack growth. We develop a continuum thermodynamics framework for a damaging medium with electromechanical coupling
subject to four different crack-face boundary conditions. A theory is presented to reproduce impermeable, permeable, conducting, and energetically consistent crack-face boundary conditions, the latter of which requires a finite deformation formulation. A primary application of hydraulic fracturing involves the injection of fluid into a perforated wellbore with the intention of fracturing the surrounding reservoir and stimulating its overall production. This process involves the coupling of fluid flow with material failure, which must account for the interactions of several cracks, both natural and man-made. Many of the questions on the effects these interactions have on the performance of the frac treatments are unanswered. We develop a continuum thermodynamics framework for fluid flow through a damaging porous medium in order to represent some of the processes and interactions that occur during hydraulic fracturing. The model will be capable of simulating both Stokes flow through cracks and Darcy flow through the porous medium. The flow is coupled to the deformation of the bulk solid medium and the evolution of cracks within the material. We utilize a finite deformation framework in order to capture the opening of the fractures, which can have substantial effects on fluid pressure response. For both models, a fully coupled non-linear finite element formulation is constructed. Several benchmark solutions are investigated to validate the expected behavior and accuracy of the method. In addition, a number of interesting problems are investigated in order to demonstrate the ability of the method to respond to various complexities like material anisotropy and the interaction of multiple cracks.
Advisors/Committee Members: Landis, Chad M. (advisor), Hughes, Thomas J.R. (committee member), Mear, Mark E. (committee member), Ravi-Chandar, Krishnaswa (committee member), Foster, John T. (committee member).
Subjects/Keywords: Phase-field; Fracture mechanics; Piezoelectric; Hydraulic fracture
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APA (6th Edition):
-0908-0089. (2016). Phase-field modeling of fracture for multiphysics problems. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/46492
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-0908-0089. “Phase-field modeling of fracture for multiphysics problems.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed March 04, 2021.
http://hdl.handle.net/2152/46492.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-0908-0089. “Phase-field modeling of fracture for multiphysics problems.” 2016. Web. 04 Mar 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-0908-0089. Phase-field modeling of fracture for multiphysics problems. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2152/46492.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-0908-0089. Phase-field modeling of fracture for multiphysics problems. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/46492
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
25.
Doungkaew, Natchanan.
Fracture aperture profiles as indicators of fracture growth environments : an integrated study of fracture aperture growth in the Campito Formation of eastern California.
Degree: MSin Geological Sciences, Geological Sciences, 2016, University of Texas – Austin
URL: http://hdl.handle.net/2152/47091
► Processes of fracture formation control flow of fluid in the subsurface and the mechanical properties of the brittle crust. I investigate whether fracture aperture profiles…
(more)
▼ Processes of
fracture formation control flow of fluid in the subsurface and the mechanical properties of the brittle crust. I investigate whether
fracture aperture profiles describing the opening displacement along their height or length reflect
fracture growth conditions and mechanisms. I hypothesize that aperture profiles of fractures growing under different environments and by different mechanisms have different ellipticity. I measured
fracture profiles for quartz cemented opening-mode fractures in low-grade metamorphic sandstone of the Campito Formation, eastern California, and quantified their ellipticity using curve fitting methods based on the Lamé function. I compare the Lamé parameter n against structural and inferred environmental parameters, including
fracture orientation,
fracture tip characteristics, locations of
fracture tips relative to layer boundaries, texture of
fracture cements, and temperature during
fracture growth as determined through fluid inclusion homogenization temperatures. Lamé n values range from 0.72 to 3.20, with the majority falling between 1 and 1.5.
Fracture with n < 2 correlate with higher fluid inclusion homogenization temperatures between 270°C and 315°C, and are preferentially filled with blocky quartz cement. Fractures with fluid inclusion temperatures in the range of 150°C and 250°C have n~ 2 and preferentially contain crack-seal quartz cement. I observe no correlation between n and
fracture orientation, and aperture/length ratio, although fractures with wide apertures have n<2.
To explain fractures with n<2 we propose a
fracture growth mechanism consisting of elastic opening increments followed by stages of stress dissipation in the
fracture tip regions. Kinematic models suggest that rapid length or height growth with slow aperture growth results in
fracture aperture profiles with n~1.
Fracture aperture profiles with n>2 require opening increments with blunt tips and slow length or height growth relative to aperture growth. Our model is consistent with faster length growth resulting from reduced
fracture toughness with increasing temperature, leading to low n at higher temperatures. The absence of crack-seal cement in fractures with low n may relate to overall fast
fracture growth at higher temperatures, with aperture growth exceeding rates of synkinematic crack-seal quartz cementation. Fractures with n>2 require tip blunting that I attribute to enhanced solution-precipitation creep by stress concentration at the
fracture tip.
Advisors/Committee Members: Eichhubl, Peter (advisor), Behr, Whitney (committee member), Fisher, William (committee member).
Subjects/Keywords: Fracture aperture profiles; Kinematic fracture growth models
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APA (6th Edition):
Doungkaew, N. (2016). Fracture aperture profiles as indicators of fracture growth environments : an integrated study of fracture aperture growth in the Campito Formation of eastern California. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/47091
Chicago Manual of Style (16th Edition):
Doungkaew, Natchanan. “Fracture aperture profiles as indicators of fracture growth environments : an integrated study of fracture aperture growth in the Campito Formation of eastern California.” 2016. Masters Thesis, University of Texas – Austin. Accessed March 04, 2021.
http://hdl.handle.net/2152/47091.
MLA Handbook (7th Edition):
Doungkaew, Natchanan. “Fracture aperture profiles as indicators of fracture growth environments : an integrated study of fracture aperture growth in the Campito Formation of eastern California.” 2016. Web. 04 Mar 2021.
Vancouver:
Doungkaew N. Fracture aperture profiles as indicators of fracture growth environments : an integrated study of fracture aperture growth in the Campito Formation of eastern California. [Internet] [Masters thesis]. University of Texas – Austin; 2016. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2152/47091.
Council of Science Editors:
Doungkaew N. Fracture aperture profiles as indicators of fracture growth environments : an integrated study of fracture aperture growth in the Campito Formation of eastern California. [Masters Thesis]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/47091
University of Texas – Austin
26.
-0053-6430.
Interactions between chemical alteration, fracture mechanics, and fluid flow in hydrothermal systems.
Degree: PhD, Geological sciences, 2018, University of Texas – Austin
URL: http://hdl.handle.net/2152/68884
► The hydromechanical properties of fault zones reflect evolving feedback between chemical, hydrological, and mechanical processes. These processes are evident in differences in fault zone architecture…
(more)
▼ The hydromechanical properties of fault zones reflect evolving feedback between chemical, hydrological, and mechanical processes. These processes are evident in differences in fault zone architecture and the mineralogical, textural, and mechanical properties of the constituent parts. In this study, I quantify each of these attributes and explore feedback pathways evident in the Dixie Valley-Stillwater fault zone, Nevada, USA. I conducted 1) double-torsion load-relaxation tests to measure mode-I
fracture toughness (KIC) and subcritical
fracture growth index (SCI) in ambient and aqueous conditions, 2) uniaxial testing to measure unconfined compressive strength (UCS) and static elastic parameters, 3) mineralogical and textural characterization of altered and damaged rock, and 4) field observations focused on the role of alteration in fault zone evolution. The first investigation explored the impact of alteration on
fracture mechanical properties of exhumed alteration assemblages, including: fumarole-related acid-sulfate alteration and silicification, silicification in an epithermal environment, quartz-kaolinite-carbonate alteration in an intermediate depth system, and calcite-chlorite-hematite alteration. The second investigation examined the impact of physiochemical conditions on
fracture growth in silicified rocks. Environments included: ambient air, deionized water, dilute HCl, NaOH, and NaCl solutions, and deionized water at elevated temperature. The third investigation employed field observations to assess the impact of alteration on fault evolution. The results from these complimentary investigations show that fault-proximal weakening or strengthening are strongly influenced by hydrothermal processes. Silicification is associated with increased KIC, SCI, UCS, and brittleness, producing fault cores as strong or stronger than adjacent damage zone material. Calcite-chlorite-hematite assemblages containing abundant unsealed microfractures are approximately six times weaker than silicified rocks. All measures of strength increase when sealing of microfractures surpasses ~85%. SCI in silicified rocks is reduced in aqueous environments, with >60% reduction in alkaline solutions, suggesting that physiochemical conditions in hydrothermal systems may facilitate
fracture growth. Field observations support the importance of alteration and precipitation in fault zone development; silicification and precipitation-strengthening contribute to thick fault cores, whereas damage and alteration-weakening promote strain localization. Together, results from these investigations highlight the important and underappreciated role of hydrothermal processes in the development of hydromechanical properties in fault zones.
Advisors/Committee Members: Eichhubl, Peter (advisor), Barnes, Jaime D (committee member), Behr, Whitney M (committee member), Davatzes, Nicholas C (committee member), Olson, Jon E (committee member), Stockli, Daniel F (committee member).
Subjects/Keywords: Fracture; Fracture toughness; Subcritical; Alteration; Hydrothermal
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APA (6th Edition):
-0053-6430. (2018). Interactions between chemical alteration, fracture mechanics, and fluid flow in hydrothermal systems. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/68884
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-0053-6430. “Interactions between chemical alteration, fracture mechanics, and fluid flow in hydrothermal systems.” 2018. Doctoral Dissertation, University of Texas – Austin. Accessed March 04, 2021.
http://hdl.handle.net/2152/68884.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-0053-6430. “Interactions between chemical alteration, fracture mechanics, and fluid flow in hydrothermal systems.” 2018. Web. 04 Mar 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-0053-6430. Interactions between chemical alteration, fracture mechanics, and fluid flow in hydrothermal systems. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2018. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/2152/68884.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-0053-6430. Interactions between chemical alteration, fracture mechanics, and fluid flow in hydrothermal systems. [Doctoral Dissertation]. University of Texas – Austin; 2018. Available from: http://hdl.handle.net/2152/68884
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Universiteit Utrecht
27.
Teunis, T.
Distal radius fractures: what determines the outcome after surgery?.
Degree: 2016, Universiteit Utrecht
URL: http://dspace.library.uu.nl:8080/handle/1874/337826
► This thesis addresses current issues in the outcome of operatively treated distal radius fractures. The general aim was to determine factors associated with adverse events,…
(more)
▼ This thesis addresses current issues in the outcome of operatively treated distal radius fractures. The general aim was to determine factors associated with adverse events, loss of motion, functional limitations, and opioid use after surgery. Injury In 3D complete articular distal radius
fracture models we determined that on average the volar lunate facet fragment is much larger than the dorsal lunate facet fragment and the radial styloid fragment had the greatest average displacement. This suggests that alignment of the volar lunate facet fragment with the radial styloid fragment may be most important in
fracture fixation. TreatmentThere is a subset of fractures that can be considered for surgery prior to an attempt at manipulative reduction and immobilization, for example due to a marginal shearing injury, significant displacement, or comminution. Patients can use a decision aid to help them choose between surgery or manipulation and immobilization. For patients who choose surgery before reduction, and who have no nerve or skin issues, we found that it’s safe to forgo reduction – and thus forgo the recommendation made by the Dutch distal radius
fracture guidelines to reduce any displaced
fracture. Our work also showed that
fracture reduction is maintained one year after fixation with a volar locking plate. We found no difference in change in
fracture position or range of motion, grip strength or disability between one and two distal screw rows. Routinely using two rows of screws seems to add unnecessary costs, a longer duration of surgery, and more opportunities for a misplaced or overly long screw. The limited association between radiographic deformity and disability is illustrated by the difference in parameters recommended by national societies to define an inadequate reduction and consider surgery. We found that no radiographic parameter was associated with symptoms or objective impairment one year after
fracture fixation. The fact that some residual displacement is not associated with impairment or patient reported outcome should be considered when counseling patients on the risks and benefits of surgical treatment. Recovery When finger stiffness and pain intensity are considered out of proportion to what is expected after distal radius
fracture, patients are sometimes labeled with illness constructions such as complex regional pain syndrome or reflex sympathetic dystrophy. We found that catastrophic thinking – the tendency to misinterpret or overinterpret nociception – was a consistent and major determinant of finger stiffness at suture removal and six weeks after injury. This shows finger stiffness occurs due to normal human illness behavior (catastrophic thinking) and subsequent fear and avoidance of activity. This causes stiffness and skin changes (swelling, shiny skin, change in hair patterns) associated with disuse. How far the
fracture fragments are apart only had a limited effect on the amount of opioids people take in a cohort from the United States. Pathophysiology may not be the main determinant of…
Advisors/Committee Members: Kon, M., Ring, D., Schuurman, A.H..
Subjects/Keywords: wrist; fracture; surgery
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APA (6th Edition):
Teunis, T. (2016). Distal radius fractures: what determines the outcome after surgery?. (Doctoral Dissertation). Universiteit Utrecht. Retrieved from http://dspace.library.uu.nl:8080/handle/1874/337826
Chicago Manual of Style (16th Edition):
Teunis, T. “Distal radius fractures: what determines the outcome after surgery?.” 2016. Doctoral Dissertation, Universiteit Utrecht. Accessed March 04, 2021.
http://dspace.library.uu.nl:8080/handle/1874/337826.
MLA Handbook (7th Edition):
Teunis, T. “Distal radius fractures: what determines the outcome after surgery?.” 2016. Web. 04 Mar 2021.
Vancouver:
Teunis T. Distal radius fractures: what determines the outcome after surgery?. [Internet] [Doctoral dissertation]. Universiteit Utrecht; 2016. [cited 2021 Mar 04].
Available from: http://dspace.library.uu.nl:8080/handle/1874/337826.
Council of Science Editors:
Teunis T. Distal radius fractures: what determines the outcome after surgery?. [Doctoral Dissertation]. Universiteit Utrecht; 2016. Available from: http://dspace.library.uu.nl:8080/handle/1874/337826
Cornell University
28.
Veilleux, Michael.
Geometrically Explicit Finite Element Modeling Of Aa7075-T651 Microstructure With Fatigue Cracks.
Degree: PhD, Civil and Environmental Engineering, 2011, Cornell University
URL: http://hdl.handle.net/1813/33578
► This dissertation is divided into three chapters, where each is an independent paper intended to be submitted as a refereed journal article. The main thrust…
(more)
▼ This dissertation is divided into three chapters, where each is an independent paper intended to be submitted as a refereed journal article. The main thrust of the research project overarching all three papers is to develop a high fidelity, geometrically explicit approach to finite element modeling fatigue at the microstructural length scale. Each paper is a study within this thrust, and the following is a sweeping overview of each study. More detailed abstracts for each paper are given at the beginning of each chapter. The paper in the first chapter is the fourth in a series of papers focused on implementing, calibrating, and validating criteria for simulating microstructurally small fatigue crack (MSFC) evolution, with high strain conditions in aluminum alloy (AA)7075-T651 as the proof-test application. MSFC evolution is divided into three stages: incubation, nucleation, and propagation. The specific focus of this paper is on the last stage, MSFC propagation, which is microstructure-governed fatigue crack growth through grains and/or along grain boundaries. Three simulated field metrics, crack tip displacement, crack-induced plastic slip localization, and maximum tangential stress ahead of the crack, previously investigated for prediction of nucleation, are investigated in this paper to determine their dependence on microstructural heterogeneities after nucleation. A total of 21 simulations are performed on a simplified baseline model of an AA7075-T651 microstructural region containing an MSFC. All three metrics are determined to be significantly dependent on the local microstructure immediately subsequent to nucleation. The particle spawning the crack and the orientation(s) of the grain(s) immediately surrounding the nucleated MSFC most influence the MSFC metrics. The paper in the second chapter focuses on the implementation of a computational framework that accurately and probabilistically models fatigue crack propagation at the microstructural scale, once again with high strain conditions in AA7075-T651 as the proof-test application. Toolsets are presented that generate and discretize statistically accurate microstructure geometry models and explicitly simulate the evolution of microstructurally small fatigue cracks. The concept is demonstrated through two model simulations and feasibility of the approach is critically evaluated. The paper in the third chapter is the fifth in the same series of papers described above for the first chapter. The focus of this paper is again on the last MSFC evolution stage, MSFC propagation. High resolution, micro-scale images of three propagating MSFC's are analyzed to determine dependencies of MSFC propagation on microstructural heterogeneities. Additionally, the three MSFC metrics studied in the first chapter - maximum tangential stresses, plastic slip localization, and crack displacements local to the crack front - are simulated in a finite element model that replicates an observed MSFC and the surrounding microstructure. The detailed observations and simulation reveal that…
Advisors/Committee Members: Ingraffea, Anthony R (chair), Zehnder, Alan Taylor (committee member), Earls, Christopher J (committee member).
Subjects/Keywords: fracture; fatigue; microstructure
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APA (6th Edition):
Veilleux, M. (2011). Geometrically Explicit Finite Element Modeling Of Aa7075-T651 Microstructure With Fatigue Cracks. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/33578
Chicago Manual of Style (16th Edition):
Veilleux, Michael. “Geometrically Explicit Finite Element Modeling Of Aa7075-T651 Microstructure With Fatigue Cracks.” 2011. Doctoral Dissertation, Cornell University. Accessed March 04, 2021.
http://hdl.handle.net/1813/33578.
MLA Handbook (7th Edition):
Veilleux, Michael. “Geometrically Explicit Finite Element Modeling Of Aa7075-T651 Microstructure With Fatigue Cracks.” 2011. Web. 04 Mar 2021.
Vancouver:
Veilleux M. Geometrically Explicit Finite Element Modeling Of Aa7075-T651 Microstructure With Fatigue Cracks. [Internet] [Doctoral dissertation]. Cornell University; 2011. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1813/33578.
Council of Science Editors:
Veilleux M. Geometrically Explicit Finite Element Modeling Of Aa7075-T651 Microstructure With Fatigue Cracks. [Doctoral Dissertation]. Cornell University; 2011. Available from: http://hdl.handle.net/1813/33578
29.
Ma, Xiaodan.
Integrated Hydraulic Fracture Placement and Design Optimization in Unconventional Gas Reservoirs.
Degree: 2013, Texas Digital Library
URL: http://hdl.handle.net/1969;
http://hdl.handle.net/2249.1/66806
► Unconventional reservoir such as tight and shale gas reservoirs has the potential of becoming the main source of cleaner energy in the 21th century. Production…
(more)
▼ Unconventional reservoir such as tight and shale gas reservoirs has the potential of becoming the main source of cleaner energy in the 21th century. Production from these reservoirs is mainly accomplished through engineered hydraulic fracturing to generate
fracture networks that provide the gas flow pathways from the rock matrix to the production wells. While hydraulic fracturing technology has progressed considerably in the last thirty years, designing the fracturing system primarily involves judgments from a team of engineers, geoscientists and geophysicists, without taking advantage of computational tools, such as numerical optimization techniques to improve short-term and long-term reservoir production.
This thesis focuses on developing novel optimization algorithms that can be used to improve the design and implementation of hydraulic fracturing in a shale gas reservoir to increase production and the net present value of unconventional assets. In particular, we consider simultaneous perturbation stochastic approximation (SPSA) and Covariance Matrix Adaptation - Evolution Strategy (CMA-ES) algorithms, which are proven very efficient in finding nearly optimal solutions. We show that with a judicious choice of control variables (continuous or discrete) we can obtain efficient algorithms for performing hydraulic
fracture optimization in unconventional reservoirs.
To achieve this, the hydraulic
fracture production optimization problem is divided into two aspects:
fracture stages placement optimization with fix stage numbers and unknown stage numbers. After check the parameters of
fracture model that could be used to simulate future reservoir behavior with a higher degree of confidence, the
fracture stages optimization is scheduling the fracturing sequence, and adjusting the
fracture stages intensity at different locations, which is similar to well placement problem. In addition to the detailed investigation of the new optimization technique, uncertainty quantification of reservoir properties and its implications on the optimization workflow is also considered in the shale gas reservoir model. Taking into account that shale gas reservoirs are highly heterogeneous systems, stochastic optimization methods are the most suitable framework for hydraulic
fracture stages placement.
Advisors/Committee Members: Gildin, Eduardo (advisor).
Subjects/Keywords: Hydraulic Fracture Placement
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APA (6th Edition):
Ma, X. (2013). Integrated Hydraulic Fracture Placement and Design Optimization in Unconventional Gas Reservoirs. (Thesis). Texas Digital Library. Retrieved from http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66806
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Ma, Xiaodan. “Integrated Hydraulic Fracture Placement and Design Optimization in Unconventional Gas Reservoirs.” 2013. Thesis, Texas Digital Library. Accessed March 04, 2021.
http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66806.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Ma, Xiaodan. “Integrated Hydraulic Fracture Placement and Design Optimization in Unconventional Gas Reservoirs.” 2013. Web. 04 Mar 2021.
Vancouver:
Ma X. Integrated Hydraulic Fracture Placement and Design Optimization in Unconventional Gas Reservoirs. [Internet] [Thesis]. Texas Digital Library; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66806.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Ma X. Integrated Hydraulic Fracture Placement and Design Optimization in Unconventional Gas Reservoirs. [Thesis]. Texas Digital Library; 2013. Available from: http://hdl.handle.net/1969; http://hdl.handle.net/2249.1/66806
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Texas A&M University
30.
Underwood, Jarrod.
Acid Fracture and Fracture Conductivity Study of Field Rock Samples.
Degree: MS, Petroleum Engineering, 2013, Texas A&M University
URL: http://hdl.handle.net/1969.1/151691
► Acid fracturing is a well stimulation strategy designed to increase the productivity of a producing well. The parameters of acid fracturing and the effects of…
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▼ Acid fracturing is a well stimulation strategy designed to increase the productivity of a producing well. The parameters of acid fracturing and the effects of acid interaction on specific rock samples can be studied experimentally. Acid injection data and
fracture conductivity measurements obtained in the research presented in this thesis yielded results that qualified and quantified the impact of a specific acid system on rock samples of varying acid solubility.
Six rock samples from a carbonate reservoir were labeled A through F to protect proprietary information included in this research. A 2% potassium chloride solution was used for the acid system and
fracture conductivity measurements to prevent clay swelling. Injection temperature, contact time, and injection rate were designed to simulate field treatment conditions. The effects of a chelating agent on
fracture conductivity were also studied.
Before and after images of the rock samples indicated that the effect of 15% hydrochloric acid on the samples was limited but correlated with the rock acid solubility. Samples E and F had a greater value of acid solubility and showed noticeable surface etching. Samples A, B, and C had lower values of acid solubility and did not show signs of surface etching. Sample D was of moderate acid solubility and showed minimal signs of surface etching.
Fracture conductivity did not correlate directly with acid solubility, but likely was a function of inherent matrix permeability based on leak-off measurements and
fracture conductivity measurements. Finally, the
fracture conductivity of Sample D increased after exposure to a chelating agent.
Commonly, acid
fracture experimental studies are carried out with outcrop rock samples. The samples have more homogenous properties and without hydrocarbon content. In this study, cores from downhole formation were used. The original condition was preserved as much as possible to simulate real field situations. However, using field rock samples does present challenges not generally associated with outcrop rock samples.
Based on the information gathered from the work presented in this thesis, conclusions were drawn concerning the effectiveness of a 15% hydrochloric acid treatment in this formation and the challenges of using field rock samples.
Advisors/Committee Members: Zhu, Ding (advisor), Hill, A D (committee member), Ugaz, Victor (committee member).
Subjects/Keywords: Acid Fracture; carbonate
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APA (6th Edition):
Underwood, J. (2013). Acid Fracture and Fracture Conductivity Study of Field Rock Samples. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/151691
Chicago Manual of Style (16th Edition):
Underwood, Jarrod. “Acid Fracture and Fracture Conductivity Study of Field Rock Samples.” 2013. Masters Thesis, Texas A&M University. Accessed March 04, 2021.
http://hdl.handle.net/1969.1/151691.
MLA Handbook (7th Edition):
Underwood, Jarrod. “Acid Fracture and Fracture Conductivity Study of Field Rock Samples.” 2013. Web. 04 Mar 2021.
Vancouver:
Underwood J. Acid Fracture and Fracture Conductivity Study of Field Rock Samples. [Internet] [Masters thesis]. Texas A&M University; 2013. [cited 2021 Mar 04].
Available from: http://hdl.handle.net/1969.1/151691.
Council of Science Editors:
Underwood J. Acid Fracture and Fracture Conductivity Study of Field Rock Samples. [Masters Thesis]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/151691
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