subject:(Fracture mechanics)

Oregon State University

1. 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)

Subjects/Keywords: Fracture Mechanics

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APA (6^th 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 (16^th Edition):

Addison, Dylan, A. “Time-Dependent Crack Growth Mechanisms in Alloy 617 at 800°C in Air.” 2017. Masters Thesis, Oregon State University. Accessed February 26, 2021. http://hdl.handle.net/1957/61609.

MLA Handbook (7^th Edition):

Addison, Dylan, A. “Time-Dependent Crack Growth Mechanisms in Alloy 617 at 800°C in Air.” 2017. Web. 26 Feb 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 Feb 26]. 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

2. Muñiz Calvente, Miguel. The generalized local model: A methodology for probabilistic assessment of fracture under different failure criteria .

Degree: 2017, Universidad de Oviedo

URL: http://hdl.handle.net/10651/40748

► When designing structural and mechanical components, the criteria of structural integrity must be accomplished. Such criteria consist in assuring that the component will perform its… (more)

▼ When designing structural and mechanical components, the criteria of structural integrity must be accomplished. Such criteria consist in assuring that the component will perform its designed function of supporting loads or any kind of actions causing stress and strains in the material without catastrophic failure. This implies, from the point of view of fracture mechanics, safe prediction of static, dynamic and fatigue failure what requires previous knowledge of the loads, but also the mechanical properties of the component material such as density, hardness, strength and toughness and the dimensions (shape, size and thickness) which should be suitable to withstand the actions operating on it. Moreover, this concept requires performing an experimental program and its statistical analysis, as well as the interpretation of the results obtained, in order to achieve the mechanical characterization of the material. The latter consists in the probabilistic definition of the critical values of the reference parameter, denoted generalized parameter (GP), that will be used as a property related to the material to predict failure of the components made of such material. In this doctoral thesis, an approach is presented aiming at providing an objective definition of the material characterization in order to guarantee transferability from the experimental results obtained, irrespective of the test chosen and the shape and size of the specimen, to the component design. This methodology, which is denoted Generalized Local Model (GLM) because it represents a general solution without restrictions of former particular local models, provides the statistical information related to the distribution of the reference parameter considered, i.e. the primary failure cumulative distribution (PFCDF), which is identified as a characteristic property of the material under study. Moreover, this allows a possible assessment and eventual selection of the generalized parameter (GP) to be made as a result of the evaluation of its suitability. After the GLM is introduced and justified, some of its extensions are presented in order to overcome some usual situations arising during the evaluation of experimental results. First, the GLM is applied to the joint evaluation of experimental data from different programs, using different specimen or even test types, as they were a unique sample. In this way, higher reliability in the derivation of the primary failure cumulative distribution function (PFCDF) is achieved. Second, a methodology is developed and applied to solve the assessment of the so-called confounded data case (concurrent flaw populations) as an extension of the GLM. This allows the PFCDF to be obtained independently of the failure type involved. Third, the extension of the GLM to the fatigue lifetime analysis is justified as a result of the conjunction of the GLM and the fatigue Weibull model developed by Castillo and Canteli. The application of the models proposed in this doctoral thesis is illustrated using practical examples, such as: a)… Advisors/Committee Members: Fernández Canteli, Alfonso Carlos (advisor).

Subjects/Keywords: Probabilistic fracture mechanics

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APA (6^th Edition):

Muñiz Calvente, M. (2017). The generalized local model: A methodology for probabilistic assessment of fracture under different failure criteria . (Doctoral Dissertation). Universidad de Oviedo. Retrieved from http://hdl.handle.net/10651/40748

Chicago Manual of Style (16^th Edition):

Muñiz Calvente, Miguel. “The generalized local model: A methodology for probabilistic assessment of fracture under different failure criteria .” 2017. Doctoral Dissertation, Universidad de Oviedo. Accessed February 26, 2021. http://hdl.handle.net/10651/40748.

MLA Handbook (7^th Edition):

Muñiz Calvente, Miguel. “The generalized local model: A methodology for probabilistic assessment of fracture under different failure criteria .” 2017. Web. 26 Feb 2021.

Vancouver:

Muñiz Calvente M. The generalized local model: A methodology for probabilistic assessment of fracture under different failure criteria . [Internet] [Doctoral dissertation]. Universidad de Oviedo; 2017. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10651/40748.

Council of Science Editors:

Muñiz Calvente M. The generalized local model: A methodology for probabilistic assessment of fracture under different failure criteria . [Doctoral Dissertation]. Universidad de Oviedo; 2017. Available from: http://hdl.handle.net/10651/40748

University of Texas – Austin

3. -7106-8163. The transition from subsonic to supersonic cracks.

Degree: PhD, Physics, 2016, University of Texas – Austin

URL: http://hdl.handle.net/2152/46608

► We present the full analytical solution for steady-state in-plane crack motion in a brittle triangular lattice. This allows quick numerical evaluation of solutions for very… (more)

▼ We present the full analytical solution for steady-state in-plane crack motion in a brittle triangular lattice. This allows quick numerical evaluation of solutions for very large systems, facilitating comparisons with continuum fracture theory. Cracks that propagate faster than the Rayleigh wave speed have been thought to be forbidden in the continuum theory, but clearly exist in lattice systems. Using our analytical methods, we examine in detail the motion of atoms around a crack tip as crack speed changes from subsonic to supersonic. Subsonic cracks feature displacement fields consistent with a stress intensity factor. For supersonic cracks, the stress intensity factor disappears. Subsonic cracks are characterized by small-amplitude, high-frequency oscillations in the vertical displacement of an atom along the crack line, while supersonic cracks have large-amplitude, low-frequency oscillations. Thus, while supersonic cracks are no less physical than subsonic cracks, the connection between microscopic and macroscopic behavior must be made in a different way. This is one reason supersonic cracks in tension had been thought not to exist. In continuum fracture theory, the energy flowing into the crack tip becomes negative or imaginary for crack speeds faster than the Rayleigh wave speed. This would suggest that supersonic cracks are not physically allowed. In response to this, we study the energy flow in our supersonic solutions in the lattice. First, we construct an energy flux vector in the lattice analogous to the Poynting vector in electromagnetism. This allows us to calculate the energy flow at each atom in the lattice. We find that there is positive energy flux into the crack tip for both subsonic and supersonic solutions in the lattice. Advisors/Committee Members: Marder, Michael P., 1960- (advisor), Hazeltine, Richard (committee member), Matzner, Richard (committee member), Morrison, Philip (committee member), Ravi-Chandar, Krishnaswamy (committee member).

Subjects/Keywords: Fracture; Crack; Mechanics

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APA (6^th Edition):

-7106-8163. (2016). The transition from subsonic to supersonic cracks. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/46608

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Chicago Manual of Style (16^th Edition):

-7106-8163. “The transition from subsonic to supersonic cracks.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed February 26, 2021. http://hdl.handle.net/2152/46608.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

MLA Handbook (7^th Edition):

-7106-8163. “The transition from subsonic to supersonic cracks.” 2016. Web. 26 Feb 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-7106-8163. The transition from subsonic to supersonic cracks. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/2152/46608.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

-7106-8163. The transition from subsonic to supersonic cracks. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/46608

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Hong Kong University of Science and Technology

4. 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 (6^th 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 (16^th 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 February 26, 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 (7^th Edition):

Xie, Tao. “Effect of electrostatic tractions on the fracture behavior of a dielectric/piezoelectric material under mechanical and/or electric loading.” 2013. Web. 26 Feb 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 Feb 26]. 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

5. 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 (6^th 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 (16^th 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 February 26, 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 (7^th Edition):

Chen, E. “Study on concrete strength under uniaxial and biaxial loadings from the view of fracture mechanics.” 2011. Web. 26 Feb 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 Feb 26]. 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

University of Texas – Austin

6. 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 (6^th 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 (16^th Edition):

Alotaibi, Talal Eid. “Applications of phase-field modeling in hydraulic fracture.” 2020. Doctoral Dissertation, University of Texas – Austin. Accessed February 26, 2021. http://dx.doi.org/10.26153/tsw/8157.

MLA Handbook (7^th Edition):

Alotaibi, Talal Eid. “Applications of phase-field modeling in hydraulic fracture.” 2020. Web. 26 Feb 2021.

Vancouver:

Alotaibi TE. Applications of phase-field modeling in hydraulic fracture. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2020. [cited 2021 Feb 26]. 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

7. -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 (6^th 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 (16^th Edition):

-0908-0089. “Phase-field modeling of fracture for multiphysics problems.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed February 26, 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 (7^th Edition):

-0908-0089. “Phase-field modeling of fracture for multiphysics problems.” 2016. Web. 26 Feb 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 Feb 26]. 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

Oregon State University

8. Keary, Paul Edward. A comparison of experimental mode I analysis methods for the interlaminar fracture toughness characterization of graphite/epoxy composite materials.

Degree: MS, Mechanical Engineering, 1984, Oregon State University

URL: http://hdl.handle.net/1957/41236

► Three approaches for evaluating mode I interlaminar strain energy release rates in graphite/epoxy composites were compared using experimental data from double cantilever beam specimens. Expressions… (more)

Subjects/Keywords: Fracture mechanics

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APA (6^th Edition):

Keary, P. E. (1984). A comparison of experimental mode I analysis methods for the interlaminar fracture toughness characterization of graphite/epoxy composite materials. (Masters Thesis). Oregon State University. Retrieved from http://hdl.handle.net/1957/41236

Chicago Manual of Style (16^th Edition):

Keary, Paul Edward. “A comparison of experimental mode I analysis methods for the interlaminar fracture toughness characterization of graphite/epoxy composite materials.” 1984. Masters Thesis, Oregon State University. Accessed February 26, 2021. http://hdl.handle.net/1957/41236.

MLA Handbook (7^th Edition):

Keary, Paul Edward. “A comparison of experimental mode I analysis methods for the interlaminar fracture toughness characterization of graphite/epoxy composite materials.” 1984. Web. 26 Feb 2021.

Vancouver:

Keary PE. A comparison of experimental mode I analysis methods for the interlaminar fracture toughness characterization of graphite/epoxy composite materials. [Internet] [Masters thesis]. Oregon State University; 1984. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/1957/41236.

Council of Science Editors:

Keary PE. A comparison of experimental mode I analysis methods for the interlaminar fracture toughness characterization of graphite/epoxy composite materials. [Masters Thesis]. Oregon State University; 1984. Available from: http://hdl.handle.net/1957/41236

Texas A&M University

9. Huang, Yu-Hsuan. On Coating Durability of Polymer Coated Sheet Metal under Plastic Deformation.

Degree: PhD, Mechanical Engineering, 2011, Texas A&M University

URL: http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7887

► Polymer coated sheet metal components find diverse applications in many industries. The manufacturing of the components generally involves forming of sheet metal into the desired… (more)

▼ Polymer coated sheet metal components find diverse applications in many industries. The manufacturing of the components generally involves forming of sheet metal into the desired shape and coating of the formed part with organic coating. An alternative manufacturing route is to coat the sheet metal first before forming. The change in the manufacturing sequence can potentially improve cost and reduce environmental impact. This approach, however, requires the coating to survive the deformation process. Thus, the effect of plastic deformation on coating adhesion is of primary interest to many engineers and researchers. This research aims at developing a methodology to predict the adhesion of coating after metal forming processes. A pull-off apparatus that measures the coating pull-off stress was used to indicate the coating adhesion strength. Several types of specimen were designed to obtain uniaxial tension, biaxial tension, and tension-compression deformation modes on pre-coated sheet by using a uniaxial tensile tester. Experimental results from two selected polymer coated sheet metals show that coating adhesion was affected by plastic deformation. An analytical model based on a virtual interface crack concept was developed to indicate the adhesion potential of the coating-substrate interface. From interfacial fracture mechanics, the initial adhesion potential is defined as the energy release rate characterized by the virtual interface crack and the initial pull-off stress. The analytical model was used to predict coating adhesion loss after deformation in uniaxial tension mode. The analytical model predictions agreed well with experimental results. Finite element analysis tool was applied to simulate more complex deformation modes in stamping of coated sheet meals. The stress field near the interface crack tip was used to calculate the energy release rate and predict the adhesion loss under different deformation modes. The predictions obtained from numerical method are also in good agreements with the experimental results in biaxial tension and tension-compression modes. The research has led to a better understanding of the effects of plastic deformation on coating adhesion. The developed adhesion test methods can be used to generate useful information on coating durability for diverse practical use. It is also expected that the results of the research will facilitate the development of better polymer coated sheet metal to be used in sheet metal forming processes. Advisors/Committee Members: Wang, Jyhwen (advisor), Gao, Xin-Lin (committee member), Karaman, Ibrahim (committee member), Ding, Yu (committee member).

Subjects/Keywords: Polyurethane; Fracture mechanics; Interfaces; Durability

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APA (6^th Edition):

Huang, Y. (2011). On Coating Durability of Polymer Coated Sheet Metal under Plastic Deformation. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7887

Chicago Manual of Style (16^th Edition):

Huang, Yu-Hsuan. “On Coating Durability of Polymer Coated Sheet Metal under Plastic Deformation.” 2011. Doctoral Dissertation, Texas A&M University. Accessed February 26, 2021. http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7887.

MLA Handbook (7^th Edition):

Huang, Yu-Hsuan. “On Coating Durability of Polymer Coated Sheet Metal under Plastic Deformation.” 2011. Web. 26 Feb 2021.

Vancouver:

Huang Y. On Coating Durability of Polymer Coated Sheet Metal under Plastic Deformation. [Internet] [Doctoral dissertation]. Texas A&M University; 2011. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7887.

Council of Science Editors:

Huang Y. On Coating Durability of Polymer Coated Sheet Metal under Plastic Deformation. [Doctoral Dissertation]. Texas A&M University; 2011. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-05-7887

University of Nairobi

10. Masu, Leonard P. M. A fracture mechanics approach to fatigue crack propagation characteristics in a locally used structural steel plate .

Degree: 1984, University of Nairobi

URL: http://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/16028

► A fracture mechanics approach was used to investigate the effects of thickness, stress ratio and configurational geometry on fatigue crack growth characteristics of a locally… (more)

Subjects/Keywords: Fracture mechanics

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APA (6^th Edition):

Masu, L. P. M. (1984). A fracture mechanics approach to fatigue crack propagation characteristics in a locally used structural steel plate . (Thesis). University of Nairobi. Retrieved from http://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/16028

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Masu, Leonard P M. “A fracture mechanics approach to fatigue crack propagation characteristics in a locally used structural steel plate .” 1984. Thesis, University of Nairobi. Accessed February 26, 2021. http://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/16028.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Masu, Leonard P M. “A fracture mechanics approach to fatigue crack propagation characteristics in a locally used structural steel plate .” 1984. Web. 26 Feb 2021.

Vancouver:

Masu LPM. A fracture mechanics approach to fatigue crack propagation characteristics in a locally used structural steel plate . [Internet] [Thesis]. University of Nairobi; 1984. [cited 2021 Feb 26]. Available from: http://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/16028.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Masu LPM. A fracture mechanics approach to fatigue crack propagation characteristics in a locally used structural steel plate . [Thesis]. University of Nairobi; 1984. Available from: http://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/16028

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Universidad de Cantabria

11. Cicero González, Sergio. Evaluación de la integridad estructural de componentes sometidos a condiciones de bajo confinamiento.

Degree: 2007, Universidad de Cantabria

URL: http://hdl.handle.net/10902/1230

► RESUMEN: En esta Tesis Doctoral se analiza el fenómeno de la pérdida de confinamiento en el plano de aplicación de la carga de componentes industriales… (more)

Subjects/Keywords: Fracture mechanics

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APA (6^th Edition):

Cicero González, S. (2007). Evaluación de la integridad estructural de componentes sometidos a condiciones de bajo confinamiento. (Doctoral Dissertation). Universidad de Cantabria. Retrieved from http://hdl.handle.net/10902/1230

Chicago Manual of Style (16^th Edition):

Cicero González, Sergio. “Evaluación de la integridad estructural de componentes sometidos a condiciones de bajo confinamiento.” 2007. Doctoral Dissertation, Universidad de Cantabria. Accessed February 26, 2021. http://hdl.handle.net/10902/1230.

MLA Handbook (7^th Edition):

Cicero González, Sergio. “Evaluación de la integridad estructural de componentes sometidos a condiciones de bajo confinamiento.” 2007. Web. 26 Feb 2021.

Vancouver:

Cicero González S. Evaluación de la integridad estructural de componentes sometidos a condiciones de bajo confinamiento. [Internet] [Doctoral dissertation]. Universidad de Cantabria; 2007. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10902/1230.

Council of Science Editors:

Cicero González S. Evaluación de la integridad estructural de componentes sometidos a condiciones de bajo confinamiento. [Doctoral Dissertation]. Universidad de Cantabria; 2007. Available from: http://hdl.handle.net/10902/1230

Michigan State University

12. Sur, Ukhwan. A numerical method for the treatment of kinked cracks in finite bodies.

Degree: PhD, Department of Metallurgy, Mechanics, and Materials Science, 1987, Michigan State University

URL: http://etd.lib.msu.edu/islandora/object/etd:35987

Subjects/Keywords: Fracture mechanics

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APA (6^th Edition):

Sur, U. (1987). A numerical method for the treatment of kinked cracks in finite bodies. (Doctoral Dissertation). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:35987

Chicago Manual of Style (16^th Edition):

Sur, Ukhwan. “A numerical method for the treatment of kinked cracks in finite bodies.” 1987. Doctoral Dissertation, Michigan State University. Accessed February 26, 2021. http://etd.lib.msu.edu/islandora/object/etd:35987.

MLA Handbook (7^th Edition):

Sur, Ukhwan. “A numerical method for the treatment of kinked cracks in finite bodies.” 1987. Web. 26 Feb 2021.

Vancouver:

Sur U. A numerical method for the treatment of kinked cracks in finite bodies. [Internet] [Doctoral dissertation]. Michigan State University; 1987. [cited 2021 Feb 26]. Available from: http://etd.lib.msu.edu/islandora/object/etd:35987.

Council of Science Editors:

Sur U. A numerical method for the treatment of kinked cracks in finite bodies. [Doctoral Dissertation]. Michigan State University; 1987. Available from: http://etd.lib.msu.edu/islandora/object/etd:35987

University of Minnesota

13. Zhu, Zhiren. A Probabilistic Model for Failure of Polycrystaline Silicon MEMS Structures.

Degree: MS, Civil Engineering, 2015, University of Minnesota

URL: http://hdl.handle.net/11299/174740

► Reliable MEMS devices are expected to have a very low failure probability, and thus it is cost-prohibitive to determine design strength values merely based on… (more)

Subjects/Keywords: failure; fracture mechanics; reliability; strength

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APA (6^th Edition):

Zhu, Z. (2015). A Probabilistic Model for Failure of Polycrystaline Silicon MEMS Structures. (Masters Thesis). University of Minnesota. Retrieved from http://hdl.handle.net/11299/174740

Chicago Manual of Style (16^th Edition):

Zhu, Zhiren. “A Probabilistic Model for Failure of Polycrystaline Silicon MEMS Structures.” 2015. Masters Thesis, University of Minnesota. Accessed February 26, 2021. http://hdl.handle.net/11299/174740.

MLA Handbook (7^th Edition):

Zhu, Zhiren. “A Probabilistic Model for Failure of Polycrystaline Silicon MEMS Structures.” 2015. Web. 26 Feb 2021.

Vancouver:

Zhu Z. A Probabilistic Model for Failure of Polycrystaline Silicon MEMS Structures. [Internet] [Masters thesis]. University of Minnesota; 2015. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/11299/174740.

Council of Science Editors:

Zhu Z. A Probabilistic Model for Failure of Polycrystaline Silicon MEMS Structures. [Masters Thesis]. University of Minnesota; 2015. Available from: http://hdl.handle.net/11299/174740

University of Windsor

14. Silva, Jorge. Fatigue Crack Growth in Steel used in Oil and Gas Pipelines.

Degree: MA, Civil and Environmental Engineering, 2011, University of Windsor

URL: https://scholar.uwindsor.ca/etd/5391

► Oil and gas pipelines are subject to cyclic loads and can develop fatigue cracks. Particularly, pipes with longitudinal fatigue cracks are of utmost importance… (more)

Subjects/Keywords: Fatigue; fracture mechanics; pipe

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APA (6^th Edition):

Silva, J. (2011). Fatigue Crack Growth in Steel used in Oil and Gas Pipelines. (Masters Thesis). University of Windsor. Retrieved from https://scholar.uwindsor.ca/etd/5391

Chicago Manual of Style (16^th Edition):

Silva, Jorge. “Fatigue Crack Growth in Steel used in Oil and Gas Pipelines.” 2011. Masters Thesis, University of Windsor. Accessed February 26, 2021. https://scholar.uwindsor.ca/etd/5391.

MLA Handbook (7^th Edition):

Silva, Jorge. “Fatigue Crack Growth in Steel used in Oil and Gas Pipelines.” 2011. Web. 26 Feb 2021.

Vancouver:

Silva J. Fatigue Crack Growth in Steel used in Oil and Gas Pipelines. [Internet] [Masters thesis]. University of Windsor; 2011. [cited 2021 Feb 26]. Available from: https://scholar.uwindsor.ca/etd/5391.

Council of Science Editors:

Silva J. Fatigue Crack Growth in Steel used in Oil and Gas Pipelines. [Masters Thesis]. University of Windsor; 2011. Available from: https://scholar.uwindsor.ca/etd/5391

Georgia Tech

15. Morgan, Joseph David. Dynamics of cracked structures using finite elements.

Degree: PhD, Engineering mechanics, 1974, Georgia Tech

URL: http://hdl.handle.net/1853/16357

Subjects/Keywords: Fracture mechanics

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APA (6^th Edition):

Morgan, J. D. (1974). Dynamics of cracked structures using finite elements. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/16357

Chicago Manual of Style (16^th Edition):

Morgan, Joseph David. “Dynamics of cracked structures using finite elements.” 1974. Doctoral Dissertation, Georgia Tech. Accessed February 26, 2021. http://hdl.handle.net/1853/16357.

MLA Handbook (7^th Edition):

Morgan, Joseph David. “Dynamics of cracked structures using finite elements.” 1974. Web. 26 Feb 2021.

Vancouver:

Morgan JD. Dynamics of cracked structures using finite elements. [Internet] [Doctoral dissertation]. Georgia Tech; 1974. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/1853/16357.

Council of Science Editors:

Morgan JD. Dynamics of cracked structures using finite elements. [Doctoral Dissertation]. Georgia Tech; 1974. Available from: http://hdl.handle.net/1853/16357

Georgia Tech

16. Hardy, Ronald Harold. A high-order finite element for two-dimensional crack problems.

Degree: PhD, Engineering mechanics, 1974, Georgia Tech

URL: http://hdl.handle.net/1853/20025

Subjects/Keywords: Fracture mechanics

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APA (6^th Edition):

Hardy, R. H. (1974). A high-order finite element for two-dimensional crack problems. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/20025

Chicago Manual of Style (16^th Edition):

Hardy, Ronald Harold. “A high-order finite element for two-dimensional crack problems.” 1974. Doctoral Dissertation, Georgia Tech. Accessed February 26, 2021. http://hdl.handle.net/1853/20025.

MLA Handbook (7^th Edition):

Hardy, Ronald Harold. “A high-order finite element for two-dimensional crack problems.” 1974. Web. 26 Feb 2021.

Vancouver:

Hardy RH. A high-order finite element for two-dimensional crack problems. [Internet] [Doctoral dissertation]. Georgia Tech; 1974. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/1853/20025.

Council of Science Editors:

Hardy RH. A high-order finite element for two-dimensional crack problems. [Doctoral Dissertation]. Georgia Tech; 1974. Available from: http://hdl.handle.net/1853/20025

Georgia Tech

17. Malluck, John Francis. Crack propagation in finite bodies.

Degree: PhD, Engineering mechanics, 1976, Georgia Tech

URL: http://hdl.handle.net/1853/15859

Subjects/Keywords: Fracture mechanics

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APA (6^th Edition):

Malluck, J. F. (1976). Crack propagation in finite bodies. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/15859

Chicago Manual of Style (16^th Edition):

Malluck, John Francis. “Crack propagation in finite bodies.” 1976. Doctoral Dissertation, Georgia Tech. Accessed February 26, 2021. http://hdl.handle.net/1853/15859.

MLA Handbook (7^th Edition):

Malluck, John Francis. “Crack propagation in finite bodies.” 1976. Web. 26 Feb 2021.

Vancouver:

Malluck JF. Crack propagation in finite bodies. [Internet] [Doctoral dissertation]. Georgia Tech; 1976. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/1853/15859.

Council of Science Editors:

Malluck JF. Crack propagation in finite bodies. [Doctoral Dissertation]. Georgia Tech; 1976. Available from: http://hdl.handle.net/1853/15859

University of Hong Kong

18. Deng, Wei. Advances in interfacial crack/inclusion problems and constitutive models in solids.

Degree: 1997, University of Hong Kong

URL: http://hdl.handle.net/10722/34639

Subjects/Keywords: Fracture mechanics.

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APA (6^th Edition):

Deng, W. (1997). Advances in interfacial crack/inclusion problems and constitutive models in solids. (Thesis). University of Hong Kong. Retrieved from http://hdl.handle.net/10722/34639

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Deng, Wei. “Advances in interfacial crack/inclusion problems and constitutive models in solids.” 1997. Thesis, University of Hong Kong. Accessed February 26, 2021. http://hdl.handle.net/10722/34639.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Deng, Wei. “Advances in interfacial crack/inclusion problems and constitutive models in solids.” 1997. Web. 26 Feb 2021.

Vancouver:

Deng W. Advances in interfacial crack/inclusion problems and constitutive models in solids. [Internet] [Thesis]. University of Hong Kong; 1997. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10722/34639.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Deng W. Advances in interfacial crack/inclusion problems and constitutive models in solids. [Thesis]. University of Hong Kong; 1997. Available from: http://hdl.handle.net/10722/34639

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Hong Kong

19. Su, Kai-leung. Fractal two-level finite element method for elastic crack analysis.

Degree: 1996, University of Hong Kong

URL: http://hdl.handle.net/10722/35013

Subjects/Keywords: Fracture mechanics.

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APA (6^th Edition):

Su, K. (1996). Fractal two-level finite element method for elastic crack analysis. (Thesis). University of Hong Kong. Retrieved from http://hdl.handle.net/10722/35013

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Su, Kai-leung. “Fractal two-level finite element method for elastic crack analysis.” 1996. Thesis, University of Hong Kong. Accessed February 26, 2021. http://hdl.handle.net/10722/35013.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Su, Kai-leung. “Fractal two-level finite element method for elastic crack analysis.” 1996. Web. 26 Feb 2021.

Vancouver:

Su K. Fractal two-level finite element method for elastic crack analysis. [Internet] [Thesis]. University of Hong Kong; 1996. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/10722/35013.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Su K. Fractal two-level finite element method for elastic crack analysis. [Thesis]. University of Hong Kong; 1996. Available from: http://hdl.handle.net/10722/35013

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Sydney

20. Davies, Benjamin Rhys. Multi-Scale Films Inspired by Bone .

Degree: 2016, University of Sydney

URL: http://hdl.handle.net/2123/15374

► The mechanical properties of bone, specifically the combination of strength and toughness, when adjusted for the mechanical properties of its constituent materials exceeds the performance… (more)

Subjects/Keywords: bone; fracture mechanics; hierarchal structure

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APA (6^th Edition):

Davies, B. R. (2016). Multi-Scale Films Inspired by Bone . (Thesis). University of Sydney. Retrieved from http://hdl.handle.net/2123/15374

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Davies, Benjamin Rhys. “Multi-Scale Films Inspired by Bone .” 2016. Thesis, University of Sydney. Accessed February 26, 2021. http://hdl.handle.net/2123/15374.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Davies, Benjamin Rhys. “Multi-Scale Films Inspired by Bone .” 2016. Web. 26 Feb 2021.

Vancouver:

Davies BR. Multi-Scale Films Inspired by Bone . [Internet] [Thesis]. University of Sydney; 2016. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/2123/15374.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Davies BR. Multi-Scale Films Inspired by Bone . [Thesis]. University of Sydney; 2016. Available from: http://hdl.handle.net/2123/15374

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

21. Alam, Mahabub. Crack Penetration and Deflection Behavior at Interfaces.

Degree: PhD, Mechanical Engineering, 2016, Oregon State University

URL: http://hdl.handle.net/1957/59907

► This study computationally and experimentally examines the mechanisms of crack penetration, deflection and the transition between penetration and deflection. The finite element analysis based computational… (more)

▼ This study computationally and experimentally examines the mechanisms of crack penetration, deflection and the transition between penetration and deflection. The finite element analysis based computational modeling work used strength-and-energy based cohesive-zone approach to study the effect of dimensionless parameters (e.g., interfacial incident angle, fracture-length scale, and normalized toughness) on penetration/deflection behavior for mode-I loading (tensile load normal to crack plane). The first modeling work examines the effect of incident angle between crack plane and interface for a crack incident on an interface. As expected, results exhibit that small incident angles cause deflection whereas penetration is more likely at large incident angles. The transition between penetration and deflection becomes more strength-ratio dependent as incident angle decreases. It appears that, facture-length scale is an influential parameter in crack deflection criterion and chances of deflection reduces as fracture-length-scale decreases. Finally, the analysis looked at the effect of normalized-toughness and found that the normalized-toughness has a small effect on deflection criteria. The second modeling work investigated the transition mechanism between deflection and penetration. The situation when both mode-I and mode-II works simultaneously is called mixed-mode, which is presented by the parameter phase angle. Phase angle 0° represents pure mode-I, 90° represents pure mode-II (shear load parallel to crack plane), and any phase angle in-between 0° and 90° represents mixed-mode. Results have shown the presence of smaller phase angle in the crack-tip at transition than deflection, while the applied load is elevated at transition due to providing the required energy for both the penetration and deflection. The difference of phase angles between transition and deflection becomes low as fracture-length-scale decreases. The results of cohesive-zone model meet Linear Elastic Fracture Mechanics (LEFM) results for the case of small fracture-length scales. This work analyzed interfacial phase angle during transition, between penetration and deflection, not only for homogeneous materials system but also for modulus mismatch. It was found that stiffer first-phase materials tend to create higher phase angle at the crack tip interfaces; the cases for low modulus mismatches are more sensitive than high modulus mismatches. A systematic experimental study was performed to compare results with the cohesive-zone method, LEFM, and strength-based method results. A brittle polymer Polymethyl methacrylate (PMMA) was used as substrate material, and two different kind of solvent adhesives Weld-On 4 and Weld-On 16 were used as interfaces that have similar elastic modulus as PMMA. The interfaces created by Weld-On 4 are weaker while Weld-On 16 creates stronger interfaces; however, they have similar toughness. Crack incident angle varied from 75° to 90° with 5° increment. Critical incident angle at transition between penetration and… Advisors/Committee Members: Parmigiani, John (advisor), Nairn, John (committee member).

Subjects/Keywords: Fracture mechanics; Fracture mechanics

…Linear Elastic Fracture Mechanics(LEFM), He and Hutchinson [17] predicted… …displacement showing the existence of an LEFM stress field at small values of material fracture… …to 90° at a fixed interface fracture length scale and fixed normalized toughness and a… …range of material fracture length scales (dashed lines)… …fracture of element three showing that elements corresponding to the lower-strength traction law…

11 more images…

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APA (6^th Edition):

Alam, M. (2016). Crack Penetration and Deflection Behavior at Interfaces. (Doctoral Dissertation). Oregon State University. Retrieved from http://hdl.handle.net/1957/59907

Chicago Manual of Style (16^th Edition):

Alam, Mahabub. “Crack Penetration and Deflection Behavior at Interfaces.” 2016. Doctoral Dissertation, Oregon State University. Accessed February 26, 2021. http://hdl.handle.net/1957/59907.

MLA Handbook (7^th Edition):

Alam, Mahabub. “Crack Penetration and Deflection Behavior at Interfaces.” 2016. Web. 26 Feb 2021.

Vancouver:

Alam M. Crack Penetration and Deflection Behavior at Interfaces. [Internet] [Doctoral dissertation]. Oregon State University; 2016. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/1957/59907.

Council of Science Editors:

Alam M. Crack Penetration and Deflection Behavior at Interfaces. [Doctoral Dissertation]. Oregon State University; 2016. Available from: http://hdl.handle.net/1957/59907

Columbia University

22. Mobasher, Mostafa. Enhanced continuum damage modeling of mechanical failure in ice and rocks.

Degree: 2017, Columbia University

URL: https://doi.org/10.7916/D85D94B8

► Modeling fracture in geomaterials is essential to the understanding of many physical phenomenon which may posses natural hazards e.g. landslides, faults and iceberg calving or… (more)

▼ Modeling fracture in geomaterials is essential to the understanding of many physical phenomenon which may posses natural hazards e.g. landslides, faults and iceberg calving or man-made processes e.g. hydraulic fracture and excavations. Continuum Damage Mechanics (CDM) models the crack as a solid region with a degraded stiffness. This continuum definition of cracks in CDM allows more feasible coupling with other forms of material non-linearity and eliminates the need to track complicated crack geometry. Using CDM to analyze fracture for the modeling of fracture in geomaterials encounters several challenges e.g.: 1) the need to model the multiple physical processes occurring in geomaterials, typically: coupled fluid flow and solid deformation, 2) the need to consider non-local damage and transport in order to capture the underlying long range interactions and achieve mesh-independent finite element solutions and 3) the elevated computational cost associated with non-linear mixed finite element formulations. The research presented in this thesis aims at improving the CDM formulations for modeling fracture geomaterials. This research can be divided into three main parts. The first is the introduction of a novel non-local damage transport formulation for modeling fracture in poroelastic media. The mathematical basis of the formulation are derived from thermodynamic equilibrium that considers non-local processes and homogenization principles. The non-local damage transport model leads to two additional regularization equations, one for non-local damage and the other for non-local transport which is reduced to non-local permeability. We consider two options for the implementation of the derived non-local transport damage model. The first option is the four-field formulation which extends the (u/P) formulation widely used in poroelasticity to include the non-local damage and transport phenomena. The second option is the three-field formulation, which is based on the coupling of the regularization equations under the assumptions of similar damage and permeability length scales and similar driving local stress/strain for the evolution of the damage and permeability. The three-field formulation is computationally cheaper but it degrades the physical modeling capabilities of the model. For each of these formulations, a non-linear mixed-finite element solution is developed and the Jacobian matrix is derived analytically. The developed formulations are used in the analysis of hydraulic fracture and consolidation examples. In the second part, a novel approach for CDM modeling of hydraulic fracture of glaciers is pretended. The presence of water-filled crevasses is known to increase the penetration depth of crevasses and this has been hypothesized to play an important role controlling iceberg calving rate. Here, we develop a continuum damage-based poro-mechanics formulation that enables the simulation of water-filled basal and/or surface crevasse propagation. The formulation incorporates a scalar isotropic damage…

Subjects/Keywords: Continuum damage mechanics – Mathematical models; Fracture mechanics; Rocks – Fracture

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APA (6^th Edition):

Mobasher, M. (2017). Enhanced continuum damage modeling of mechanical failure in ice and rocks. (Doctoral Dissertation). Columbia University. Retrieved from https://doi.org/10.7916/D85D94B8

Chicago Manual of Style (16^th Edition):

Mobasher, Mostafa. “Enhanced continuum damage modeling of mechanical failure in ice and rocks.” 2017. Doctoral Dissertation, Columbia University. Accessed February 26, 2021. https://doi.org/10.7916/D85D94B8.

MLA Handbook (7^th Edition):

Mobasher, Mostafa. “Enhanced continuum damage modeling of mechanical failure in ice and rocks.” 2017. Web. 26 Feb 2021.

Vancouver:

Mobasher M. Enhanced continuum damage modeling of mechanical failure in ice and rocks. [Internet] [Doctoral dissertation]. Columbia University; 2017. [cited 2021 Feb 26]. Available from: https://doi.org/10.7916/D85D94B8.

Council of Science Editors:

Mobasher M. Enhanced continuum damage modeling of mechanical failure in ice and rocks. [Doctoral Dissertation]. Columbia University; 2017. Available from: https://doi.org/10.7916/D85D94B8

Michigan State University

23. Wente, Anthony. Interlaminar fracture toughness of a quasi-3D composite.

Degree: 2019, Michigan State University

URL: http://etd.lib.msu.edu/islandora/object/etd:48348

►

Thesis M.S. Michigan State University. Mechanical Engineering 2019.

Fiber reinforced polymer (FRP) composites are a heavily sought-after material for light-weighting components in next generation vehicles… (more)

Subjects/Keywords: Carbon fiber-reinforced plastics – Fracture; Fibrous composites – Fracture; Fracture mechanics; Mechanical engineering; Aerospace engineering; Mechanics

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APA (6^th Edition):

Wente, A. (2019). Interlaminar fracture toughness of a quasi-3D composite. (Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:48348

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Wente, Anthony. “Interlaminar fracture toughness of a quasi-3D composite.” 2019. Thesis, Michigan State University. Accessed February 26, 2021. http://etd.lib.msu.edu/islandora/object/etd:48348.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Wente, Anthony. “Interlaminar fracture toughness of a quasi-3D composite.” 2019. Web. 26 Feb 2021.

Vancouver:

Wente A. Interlaminar fracture toughness of a quasi-3D composite. [Internet] [Thesis]. Michigan State University; 2019. [cited 2021 Feb 26]. Available from: http://etd.lib.msu.edu/islandora/object/etd:48348.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Wente A. Interlaminar fracture toughness of a quasi-3D composite. [Thesis]. Michigan State University; 2019. Available from: http://etd.lib.msu.edu/islandora/object/etd:48348

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Pretoria

24. [No author]. Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems .

Degree: 2007, University of Pretoria

URL: http://upetd.up.ac.za/thesis/available/etd-04172007-115809/

► This thesis deals with the solution of linear elastic fracture mechanics problems. To solve the linear elastic fracture mechanics problems, the finite element method and… (more)

▼ This thesis deals with the solution of linear elastic fracture mechanics problems. To solve the linear elastic fracture mechanics problems, the finite element method and path independent integrals are employed, namely Rice's J integral and an alternative path independent integral I *, which is the energy complement to J. Stress intensity factors for typical mode I and mode II fracture mechanics problems in isotropic and orthotropic elastic plates are calculated. The problems considered are a center cracked panel subjected to uniform tension, a single edge cracked panel subjected to uniform tension, a double edge cracked panel subjected to uniform tension, and a center cracked panel subjected to uniform shear. Firstly, classical displacement based finite elements, elements with penalized equilibrium and elements with drilling degrees of freedom are presented and implemented in a MATLAB environment. Secondly, two different ways to evaluate the stress intensity factor are considered, namely the displacement extrapolation approach, and the path independent integrals J and I *. The numerical implementation and path independence of the J and I * integral is demonstrated. It is shown that the J integral can estimate the lower bound of the stress intensity factor when used with displacement based finite elements, while the I * integral can estimate the upper bound of the stress intensity factor, when used with stress equilibrium elements. Thirdly, the path independent integrals J and I * are applied to isotropic fracture mechanics problems to determine the stress intensity factor at the tip of a crack. Convergence studies are presented to investigate the influence of mesh refinement on the stress intensity factor predicted using the J and I * integral. The path independence of J and I * are investigated. Numerical results for typical fracture specimens are presented and discussed. Finally, the path independent integrals J and I * are applied to orthotropic fracture mechanics problems to determine the stress intensity factor at the crack tip. Again, convergence studies are done, and the path independence of J and I * are investigated for orthotropic problems. Numerical results for typical fracture specimens are presented and discussed. The effect of the degree of anisotropy and fiber orientation on the stress intensity factor is also demonstrated. A novel contribution in this thesis are the results for elements with drilling degrees of freedom in fracture mechanics problems. In addition, the results presented here may serve to clarify published stress intensity factor results for orthotropic materials presented in the literature, since many of the results previously presented are contradictory. Advisors/Committee Members: Prof A A Groenwold (advisor), Mnr A G Visser (advisor), Dr R K L Su (advisor).

Subjects/Keywords: Fracture mechanics; UCTD

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APA (6^th Edition):

author], [. (2007). Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems . (Masters Thesis). University of Pretoria. Retrieved from http://upetd.up.ac.za/thesis/available/etd-04172007-115809/

Chicago Manual of Style (16^th Edition):

author], [No. “Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems .” 2007. Masters Thesis, University of Pretoria. Accessed February 26, 2021. http://upetd.up.ac.za/thesis/available/etd-04172007-115809/.

MLA Handbook (7^th Edition):

author], [No. “Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems .” 2007. Web. 26 Feb 2021.

Vancouver:

author] [. Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems . [Internet] [Masters thesis]. University of Pretoria; 2007. [cited 2021 Feb 26]. Available from: http://upetd.up.ac.za/thesis/available/etd-04172007-115809/.

Council of Science Editors:

author] [. Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems . [Masters Thesis]. University of Pretoria; 2007. Available from: http://upetd.up.ac.za/thesis/available/etd-04172007-115809/

Anna University

25. Vijayakumar A. A study on fracture of components With short cracks using threshold Methods;.

Degree: A study on fracture of components With short cracks using threshold Methods, 2015, Anna University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/39884

►

The concept of defect tolerant design is perhaps the major newlinejustification for the use of fracture mechanics This concept accepts the newlinepossibility that an element… (more)

Subjects/Keywords: Linear Elastic Fracture Mechanics; Stress Intensity Factor

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APA (6^th Edition):

A, V. (2015). A study on fracture of components With short cracks using threshold Methods;. (Thesis). Anna University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/39884

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

A, Vijayakumar. “A study on fracture of components With short cracks using threshold Methods;.” 2015. Thesis, Anna University. Accessed February 26, 2021. http://shodhganga.inflibnet.ac.in/handle/10603/39884.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

A, Vijayakumar. “A study on fracture of components With short cracks using threshold Methods;.” 2015. Web. 26 Feb 2021.

Vancouver:

A V. A study on fracture of components With short cracks using threshold Methods;. [Internet] [Thesis]. Anna University; 2015. [cited 2021 Feb 26]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/39884.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

A V. A study on fracture of components With short cracks using threshold Methods;. [Thesis]. Anna University; 2015. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/39884

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Texas A&M University

26. Huang, Jian. Geomechanical Development of Fractured Reservoirs During Gas Production.

Degree: PhD, Petroleum Engineering, 2013, Texas A&M University

URL: http://hdl.handle.net/1969.1/149448

► Within fractured reservoirs, such as tight gas reservoir, coupled processes between matrix deformation and fluid flow are very important for predicting reservoir behavior, pore pressure… (more)

▼ Within fractured reservoirs, such as tight gas reservoir, coupled processes between matrix deformation and fluid flow are very important for predicting reservoir behavior, pore pressure evolution and fracture closure. To study the coupling between gas desorption and rock matrix/fracture deformation, a poroelastic constitutive relation is developed and used for deformation of gas shale. Local continuity equation of dry gas model is developed by considering the mass conservation of gas, including both free and absorbed phases. The absorbed gas content and the sorption-induced volumetric strain are described through a Langmiur-type equation. A general porosity model that differs from other empirical correlations in the literature is developed and utilized in a finite element model to coupled gas diffusion and rock mass deformation. The dual permeability method (DPM) is implemented into the Finite Element Model (FEM) to investigate fracture deformation and closure and its impact on gas flow in naturally fractured reservoir. Within the framework of DPM, the fractured reservoir is treated as dual continuum. Two independent but overlapping meshes (or elements) are used to represent these kinds of reservoirs: one is the matrix elements used for deformation and fluid flow within matrix domain; while the other is the fracture element simulating the fluid flow only through the fractures. Both matrix and fractures are assumed to be permeable and can accomodate fluid transported. A quasi steady-state function is used to quantify the flow that is transferred between rock mass and fractures. By implementing the idea of equivalent fracture permeability and shape-factor within the transfer function into DPM, the fracture geometry and orientation are numerically considered and the complexity of the problem is well reduced. Both the normal deformation and shear dilation of fractures are considered and the stress-dependent fracture aperture can be updated in time. Further, a non-linear numerical model is constructed by implementing a poroviscoelastic model into the dual permeability (DPM)-finite element model (FEM) to investigate the coupled time-dependent viscoelastic deformation, fracture network evolution and compressible fluid flow in gas shale reservoir. The viscoelastic effect is addressed in both deviatoric and symmetric effective stresses to emphasize the effect of shear strain localization on fracture shear dilation. The new mechanical model is first verified with an analytical solution in a simple wellbore creep problem and then compared with the poroelastic solution in both wellbore and field cases. Advisors/Committee Members: Ghassemi, Ahmad (advisor), Aubeny, Charles (committee member), Ayers, Walter (committee member), Holditch, Stephen (committee member), Schubert, Jerome (committee member).

Subjects/Keywords: gas shale; fracture mechanics; poroelasticity; poroviscoelasticity; creep

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Huang, J. (2013). Geomechanical Development of Fractured Reservoirs During Gas Production. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/149448

Chicago Manual of Style (16^th Edition):

Huang, Jian. “Geomechanical Development of Fractured Reservoirs During Gas Production.” 2013. Doctoral Dissertation, Texas A&M University. Accessed February 26, 2021. http://hdl.handle.net/1969.1/149448.

MLA Handbook (7^th Edition):

Huang, Jian. “Geomechanical Development of Fractured Reservoirs During Gas Production.” 2013. Web. 26 Feb 2021.

Vancouver:

Huang J. Geomechanical Development of Fractured Reservoirs During Gas Production. [Internet] [Doctoral dissertation]. Texas A&M University; 2013. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/1969.1/149448.

Council of Science Editors:

Huang J. Geomechanical Development of Fractured Reservoirs During Gas Production. [Doctoral Dissertation]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/149448

Penn State University

27. Kumar, Sandeep. Fracture mechanics of nanoscale thin films.

Degree: 2012, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/15164

► Thin films are prevalently used in micro-electronics, data storage, sensors and actuators, energy conversion and micro-electro-mechanical systems, where they experience mechanical and thermal loading during… (more)

▼ Thin films are prevalently used in micro-electronics, data storage, sensors and actuators, energy conversion and micro-electro-mechanical systems, where they experience mechanical and thermal loading during device fabrication and operation. Fundamental understanding of the mechanics of deformation and fracture of thin films is therefore important from device design and reliability perspectives. This thesis pursues an experimental approach to understand deformation behavior of nanoscale thin films. A micro electro mechanical system (MEMS) based device has been developed to carry out fracture testing of metallic and multilayer thin films in-situ inside the transmission electron microscope (TEM). Nanofabrication techniques are utilized to fabricate a bent beam thermal actuator device integrated with notched fracture testing specimens. The experimental results suggest significant deviation from classical relationship between grain size and underlying deformation mechanism. A key contribution of this research is the size effect on stress concentration. Typically, geometrically necessary dislocations result in strain gradient at the notch tip. However, our in-situ selected area electron diffraction (SAED) studies clearly show the absence of any strain gradient at the notch tip. To explain this anomalous observation, we propose that when the grain size is below a critical size (for aluminum ~ 60 nm), dislocation based plasticity mechanisms are replaced by grain rotation, which homogenize the strain field. In the absence of strain (or stress) concentration, the material becomes flaw tolerant. This behavior is similar to behavior shown by naturally occurring biomaterials. We repeated the experiments on Platinum thin films with grain size favorable for dislocation based mechanics to support our hypothesis. Pure metals do not exhibit solid-solid phase transformation since they deform and fail far below the theoretically required stress levels that exceed hundreds of GPa. A key contribution of this research is to show experimentally that by controlling grain size and thickness, classical deformation modes can be suppressed to induce phase transformation in pure metal films at stresses few orders of magnitude lower than theoretical values. For the first time, we present in-situ transmission electron diffraction evidence of face-centered cubic (FCC) to hexagonal ω phase transformation in 99.99% pure nanocrystalline aluminum at room temperature and only 2.5 GPa of tensile stress. For 60 nm average grain size, the aluminum films did not show any appreciable diffusion-based processes such as grain growth, rotation and sliding. Facilitated by the absence of dislocation and diffusion based processes, the uniaxial nature of specimen loading results in phase transformation at stresses two orders of magnitude lower than that predicted for aluminum. We propose that in absence of dislocations and grain rotation, phase transformation could be the only way to relax the high strain energy at the notch tip without initiating failure, which… Advisors/Committee Members: Md Amanul Haque, Dissertation Advisor/Co-Advisor, Md Amanul Haque, Committee Chair/Co-Chair, Asok Ray, Committee Member, Eric M Mockensturm, Committee Member, Sulin Zhang, Committee Member, Douglas Edward Wolfe, Committee Member.

Subjects/Keywords: Thin films; TEM; Fracture; mechanics; nanoscale

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kumar, S. (2012). Fracture mechanics of nanoscale thin films. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/15164

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kumar, Sandeep. “Fracture mechanics of nanoscale thin films.” 2012. Thesis, Penn State University. Accessed February 26, 2021. https://submit-etda.libraries.psu.edu/catalog/15164.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kumar, Sandeep. “Fracture mechanics of nanoscale thin films.” 2012. Web. 26 Feb 2021.

Vancouver:

Kumar S. Fracture mechanics of nanoscale thin films. [Internet] [Thesis]. Penn State University; 2012. [cited 2021 Feb 26]. Available from: https://submit-etda.libraries.psu.edu/catalog/15164.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kumar S. Fracture mechanics of nanoscale thin films. [Thesis]. Penn State University; 2012. Available from: https://submit-etda.libraries.psu.edu/catalog/15164

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Pretoria

28. De Klerk, Antoinette. Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems.

Degree: Mechanical and Aeronautical Engineering, 2007, University of Pretoria

URL: http://hdl.handle.net/2263/23983

► This thesis deals with the solution of linear elastic fracture mechanics problems. To solve the linear elastic fracture mechanics problems, the finite element method and… (more)

▼ This thesis deals with the solution of linear elastic fracture mechanics problems. To solve the linear elastic fracture mechanics problems, the finite element method and path independent integrals are employed, namely Rice's J integral and an alternative path independent integral I *, which is the energy complement to J. Stress intensity factors for typical mode I and mode II fracture mechanics problems in isotropic and orthotropic elastic plates are calculated. The problems considered are a center cracked panel subjected to uniform tension, a single edge cracked panel subjected to uniform tension, a double edge cracked panel subjected to uniform tension, and a center cracked panel subjected to uniform shear. Firstly, classical displacement based finite elements, elements with penalized equilibrium and elements with drilling degrees of freedom are presented and implemented in a MATLAB environment. Secondly, two different ways to evaluate the stress intensity factor are considered, namely the displacement extrapolation approach, and the path independent integrals J and I *. The numerical implementation and path independence of the J and I * integral is demonstrated. It is shown that the J integral can estimate the lower bound of the stress intensity factor when used with displacement based finite elements, while the I * integral can estimate the upper bound of the stress intensity factor, when used with stress equilibrium elements. Thirdly, the path independent integrals J and I * are applied to isotropic fracture mechanics problems to determine the stress intensity factor at the tip of a crack. Convergence studies are presented to investigate the influence of mesh refinement on the stress intensity factor predicted using the J and I * integral. The path independence of J and I * are investigated. Numerical results for typical fracture specimens are presented and discussed. Finally, the path independent integrals J and I * are applied to orthotropic fracture mechanics problems to determine the stress intensity factor at the crack tip. Again, convergence studies are done, and the path independence of J and I * are investigated for orthotropic problems. Numerical results for typical fracture specimens are presented and discussed. The effect of the degree of anisotropy and fiber orientation on the stress intensity factor is also demonstrated. A novel contribution in this thesis are the results for elements with drilling degrees of freedom in fracture mechanics problems. In addition, the results presented here may serve to clarify published stress intensity factor results for orthotropic materials presented in the literature, since many of the results previously presented are contradictory. Advisors/Committee Members: Prof A A Groenwold (advisor), Mnr A G Visser (advisor), Dr R K L Su (advisor).

Subjects/Keywords: Fracture mechanics; UCTD

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

De Klerk, A. (2007). Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/23983

Chicago Manual of Style (16^th Edition):

De Klerk, Antoinette. “Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems.” 2007. Masters Thesis, University of Pretoria. Accessed February 26, 2021. http://hdl.handle.net/2263/23983.

MLA Handbook (7^th Edition):

De Klerk, Antoinette. “Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems.” 2007. Web. 26 Feb 2021.

Vancouver:

De Klerk A. Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems. [Internet] [Masters thesis]. University of Pretoria; 2007. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/2263/23983.

Council of Science Editors:

De Klerk A. Elements with penalized equilibrium and rotational degrees of freedom in fracture mechanics problems. [Masters Thesis]. University of Pretoria; 2007. Available from: http://hdl.handle.net/2263/23983

University of Adelaide

29. Khanna, Aditya. A new solution for an edge dislocation with applications to the stress and fracture analysis of multilayered media.

Degree: 2015, University of Adelaide

URL: http://hdl.handle.net/2440/100862

► The stress and fracture analysis of multilayered materials and structures containing crack-like defects is of interest in many research areas, such as composites, bio-mechanics, and… (more)

▼ The stress and fracture analysis of multilayered materials and structures containing crack-like defects is of interest in many research areas, such as composites, bio-mechanics, and geomechanics, and engineering applications, such as coatings, electronics, and adhesive joints. The main objective of this thesis is to further develop a general methodology and utilise it for the examination of fracture problems in multilayered materials. The general methodology is based upon the distributed dislocation technique and edge dislocation solutions obtained within the framework of plane theory of linear elasticity. This methodology has been shaped by the seminal contributions of many researchers over the past fifty years and currently represents a powerful tool for the analysis of crack problems. New theoretical models and techniques are developed in the present thesis for a range of multi-disciplinary problems utilising the adopted methodology. The research gaps and objectives are formulated specifically for each problem and discussed in separate chapters of this thesis. The solution of each of these problems represents an original and substantial contribution towards the respective area of research. The significant outcomes of this thesis include: a new approach for the analysis of reinforced cracks in layered media, a new mechanism for height control of hydraulic fractures in layered hydrocarbon reservoirs, and a new predictive model for skier-triggered avalanches. The original contributions of this thesis also include a new fundamental solution for an interfacial edge dislocation, which recovers all previously published solutions for edge dislocations in isotropic multilayered media. The obtained solution can be utilised to derive the governing integral equations for a wide variety of quasi-static crack problems in linearly elastic and isotropic multilayered materials, without any restrictions on the crack orientation or number of elastic layers. Therefore, the newly obtained solution further extends the general methodology to effectively solve a wide class of fracture problems in multilayered materials and structures. This thesis is presented in the form of a compendium of publications in high impact specialist journals. The main body of the thesis contains four articles which are united by the above mentioned theme and methodology. Three appendices are also included, which represent a compilation of the candidate’s publications on related topics. A complete publication list is provided in the forthcoming pages. Advisors/Committee Members: Kotousov, Andrei Georgievich (advisor), School of Mechanical Engineering (school).

Subjects/Keywords: fracture mechanics; multilayered materials; distributed dislocation technique

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APA (6^th Edition):

Khanna, A. (2015). A new solution for an edge dislocation with applications to the stress and fracture analysis of multilayered media. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/100862

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Khanna, Aditya. “A new solution for an edge dislocation with applications to the stress and fracture analysis of multilayered media.” 2015. Thesis, University of Adelaide. Accessed February 26, 2021. http://hdl.handle.net/2440/100862.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Khanna, Aditya. “A new solution for an edge dislocation with applications to the stress and fracture analysis of multilayered media.” 2015. Web. 26 Feb 2021.

Vancouver:

Khanna A. A new solution for an edge dislocation with applications to the stress and fracture analysis of multilayered media. [Internet] [Thesis]. University of Adelaide; 2015. [cited 2021 Feb 26]. Available from: http://hdl.handle.net/2440/100862.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Khanna A. A new solution for an edge dislocation with applications to the stress and fracture analysis of multilayered media. [Thesis]. University of Adelaide; 2015. Available from: http://hdl.handle.net/2440/100862

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Delft University of Technology

30. Opraus, Thomas (author). Determining the suitability and application of CNT test specimens for failure assesment of welded high strength steels: Are Circumferentially Notched Tensile test specimens suitable and applicable for failure assessment of (welded) S690QT steel?.

Degree: 2017, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:03435526-a66f-478f-b177-eaef0938e108

► Research has shown the Circumferentially Notched Tensile (CNT) Specimen to potentially be a size-independent fracture toughness specimen. This research focusses on expanding the practical applicability… (more)

▼ Research has shown the Circumferentially Notched Tensile (CNT) Specimen to potentially be a size-independent fracture toughness specimen. This research focusses on expanding the practical applicability of the CNT specimen as well as using it to perform fracture toughness tests on S690QT steel and simulated CGHAZ material in S690. Based on literature research the research goals of the research were to investigate different pre-cracking methods with the focus of creating cracks with little or no eccentricity, improve the accuracy of CTOD measurements, determine the equivalency between CNT and conventional fracture toughness, determine the size of the plastic zone at the crack tip specimen and find alternative methods of microstructure simulation. In order to improve pre-cracking rotational bending (RB) and standalone compression – compression (C-C) fatigue were used, both lead to low eccentricity cracks, where the length of the crack could be influenced by changing the process parameters or specimen geometry. Room temperature CTOD measurements were performed on both, where RB specimen showed an average CTOD of 0.12 mm and C-C specimen of 0.18 mm. This difference is believed to be caused by the unique stress free situation at the crack tip of the C-C specimen. By using digital image correlation (DIC) and optical microscopy, the most accurate approximation of the CTOD was determined by comparing extensometer data to optical measurements. Influence of the eccentricity of the ligament was on the fracture toughness was found to increase for brittle material. Equivalency between CNT and conventional specimen was determined by comparing both RB and C-C specimen’s CTOD at low temperature (-100 °C). C-C specimen were found to show comparable fracture toughness, while RB showed an increased value. The size of the plastic zone was measured using EBSD, measurements on annealed S690 and low carbon steel failed to show distinctive plasticity, possibly caused by insufficient plastic strain. Inductive heating was tested as a replacement for Gleeble heat treatment with promising results, however the Gleeble was used for producing all S690 CGHAZ samples. C-C was found to be the only viable pre-fatiguing method, creating average crack length extensions of 0.49mm and an eccentricity of 0.18 mm. CNT results showed a slightly lower room temperature CTOD compared to conventional specimen (0.12 mm vs 0.08 mm), low temperature results showed comparable CTOD values. More research is recommended in further development of the new standalone C-C pre-fatiguing method, improving the inductive heating and cooling setup, expanding the DIC test setup, determining the plastic zone size by performing more EBSD measurements or by performing nanoindentation measurements and using CNT specimen on very brittle materials. Advisors/Committee Members: Riemslag, Ton (graduation committee), Popovich, Vera (mentor), Delft University of Technology (degree granting institution).

Subjects/Keywords: Fracture mechanics; Materials science; CNT specimen

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APA (6^th Edition):

Opraus, T. (. (2017). Determining the suitability and application of CNT test specimens for failure assesment of welded high strength steels: Are Circumferentially Notched Tensile test specimens suitable and applicable for failure assessment of (welded) S690QT steel?. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:03435526-a66f-478f-b177-eaef0938e108

Chicago Manual of Style (16^th Edition):

Opraus, Thomas (author). “Determining the suitability and application of CNT test specimens for failure assesment of welded high strength steels: Are Circumferentially Notched Tensile test specimens suitable and applicable for failure assessment of (welded) S690QT steel?.” 2017. Masters Thesis, Delft University of Technology. Accessed February 26, 2021. http://resolver.tudelft.nl/uuid:03435526-a66f-478f-b177-eaef0938e108.

MLA Handbook (7^th Edition):

Opraus, Thomas (author). “Determining the suitability and application of CNT test specimens for failure assesment of welded high strength steels: Are Circumferentially Notched Tensile test specimens suitable and applicable for failure assessment of (welded) S690QT steel?.” 2017. Web. 26 Feb 2021.

Vancouver:

Opraus T(. Determining the suitability and application of CNT test specimens for failure assesment of welded high strength steels: Are Circumferentially Notched Tensile test specimens suitable and applicable for failure assessment of (welded) S690QT steel?. [Internet] [Masters thesis]. Delft University of Technology; 2017. [cited 2021 Feb 26]. Available from: http://resolver.tudelft.nl/uuid:03435526-a66f-478f-b177-eaef0938e108.

Council of Science Editors:

Opraus T(. Determining the suitability and application of CNT test specimens for failure assesment of welded high strength steels: Are Circumferentially Notched Tensile test specimens suitable and applicable for failure assessment of (welded) S690QT steel?. [Masters Thesis]. Delft University of Technology; 2017. Available from: http://resolver.tudelft.nl/uuid:03435526-a66f-478f-b177-eaef0938e108

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Open Access Theses and Dissertations