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Phase-Field Modeling of Fracture in Heterogeneous Materials: A Microstructure Sensitive Approach
Phase-Field Modeling of Fracture in Heterogeneous Materials: A Microstructure Sensitive Approach
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20260202105305
- ISBN
- 9798265483607
- DDC
- 531
- 서명/저자
- Phase-Field Modeling of Fracture in Heterogeneous Materials: A Microstructure Sensitive Approach
- 발행사항
- [Sl] : Northwestern University, 2025
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2025
- 형태사항
- 117 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 87-06, Section: B.
- 주기사항
- Advisor: Voorhees, Peter W.
- 학위논문주기
- Thesis (Ph.D.)--Northwestern University, 2025.
- 초록/해제
- 요약Fracture is one of the most important failure mechanisms in materials due to its catastrophic nature. Although fracture has been studied in the macro-scale through fracture mechanics, there are gaps in the understanding of how cracks interact with microstructural heterogeneities like grain boundaries and inclusions.Firstly, phase-field fracture simulations are used to study stress singularities near grain boundaries. Scaling boundary conditions based on analytical Mode-I stresses are applied to compute stress singularity exponents near the crack tips at bi-material interfaces. Grain boundaries are sampled from the five dimensional space of their macroscopic degrees of freedom. Singularity exponents are computed for the sampled grain boundaries to obtain trends as a function of misorientation variation and grain boundary plane normal variation. Using the insights gained from the computed exponents, time-dependent simulations are performed to simulate crack behavior near grain boundaries. Effects of elastic anisotropy is studied in comparison with isotropic cases, and the results are in agreement with the computed singularity exponents. Therefore, it becomes possible to engineer the microstructure to improve fracture toughness by selecting grain boundaries that offer more resistance to crack propagation.Secondly, phase-field fracture simulations are assessed using microstructures obtained from high-energy diffraction microscopy experimental data. The double cleavage drilled compression (DCDC) geometry used in the experiments is analyzed and optimized to get stable crack propagation in the simulations. J-integral studies are performed to obtain a metric that correlates to the effective toughness of the microstructure in the DCDC geometry. The experimental microstructure is converted to a suitable finite element mesh for simulations using a series of analysis techniques including clustering and graph-coloring algorithms. The obtained meshes are compared with tessellation approaches, and a polycrystalline simulation is performed to obtain the crack predictions from the phase-field model. Through the developed methodology, it becomes possible to enable direct comparison between phase-field fracture predictions and experimental observations.Finally, phase-field models for microstructure evolution are employed to analyze phase-separation behavior in Niobium-Silicon interfaces present in superconducting qubits (transmons). The Cahn-Hilliard model is used to explain incipient phase formation observed in Atom Probe Tomography data. Further, the Cahn-Hilliard model and a multi-phase multi-order parameter phase-field model are used to understand evolution of the microstructural layers identified from Transmission Electron Microscopy characterization of the Nb/Si interface.
- 일반주제명
- Mechanics
- 일반주제명
- Computational physics
- 일반주제명
- Materials science
- 일반주제명
- Engineering
- 키워드
- Grain boundary
- 기타저자
- Northwestern University Materials Science and Engineering
- 기본자료저록
- Dissertations Abstracts International. 87-06B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■006m o d
■007cr#unu||||||||
■020 ▼a9798265483607
■035 ▼a(MiAaPQ)AAI32283027
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a531
■1001 ▼aRamesh, Mythreyi.
■24510▼aPhase-Field Modeling of Fracture in Heterogeneous Materials: A Microstructure Sensitive Approach
■260 ▼a[Sl]▼bNorthwestern University▼c2025
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2025
■300 ▼a117 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 87-06, Section: B.
■500 ▼aAdvisor: Voorhees, Peter W.
■5021 ▼aThesis (Ph.D.)--Northwestern University, 2025.
■520 ▼aFracture is one of the most important failure mechanisms in materials due to its catastrophic nature. Although fracture has been studied in the macro-scale through fracture mechanics, there are gaps in the understanding of how cracks interact with microstructural heterogeneities like grain boundaries and inclusions.Firstly, phase-field fracture simulations are used to study stress singularities near grain boundaries. Scaling boundary conditions based on analytical Mode-I stresses are applied to compute stress singularity exponents near the crack tips at bi-material interfaces. Grain boundaries are sampled from the five dimensional space of their macroscopic degrees of freedom. Singularity exponents are computed for the sampled grain boundaries to obtain trends as a function of misorientation variation and grain boundary plane normal variation. Using the insights gained from the computed exponents, time-dependent simulations are performed to simulate crack behavior near grain boundaries. Effects of elastic anisotropy is studied in comparison with isotropic cases, and the results are in agreement with the computed singularity exponents. Therefore, it becomes possible to engineer the microstructure to improve fracture toughness by selecting grain boundaries that offer more resistance to crack propagation.Secondly, phase-field fracture simulations are assessed using microstructures obtained from high-energy diffraction microscopy experimental data. The double cleavage drilled compression (DCDC) geometry used in the experiments is analyzed and optimized to get stable crack propagation in the simulations. J-integral studies are performed to obtain a metric that correlates to the effective toughness of the microstructure in the DCDC geometry. The experimental microstructure is converted to a suitable finite element mesh for simulations using a series of analysis techniques including clustering and graph-coloring algorithms. The obtained meshes are compared with tessellation approaches, and a polycrystalline simulation is performed to obtain the crack predictions from the phase-field model. Through the developed methodology, it becomes possible to enable direct comparison between phase-field fracture predictions and experimental observations.Finally, phase-field models for microstructure evolution are employed to analyze phase-separation behavior in Niobium-Silicon interfaces present in superconducting qubits (transmons). The Cahn-Hilliard model is used to explain incipient phase formation observed in Atom Probe Tomography data. Further, the Cahn-Hilliard model and a multi-phase multi-order parameter phase-field model are used to understand evolution of the microstructural layers identified from Transmission Electron Microscopy characterization of the Nb/Si interface.
■590 ▼aSchool code: 0163.
■650 4▼aMechanics
■650 4▼aComputational physics
■650 4▼aMaterials science
■650 4▼aEngineering
■653 ▼aGrain boundary
■653 ▼aHigh Energy Diffraction Microscopy
■653 ▼aPhase-field fracture
■653 ▼aPhase-field grain growth
■653 ▼aPolycrystalline fracture
■690 ▼a0794
■690 ▼a0346
■690 ▼a0216
■690 ▼a0537
■71020▼aNorthwestern University▼bMaterials Science and Engineering.
■7730 ▼tDissertations Abstracts International▼g87-06B.
■790 ▼a0163
■791 ▼aPh.D.
■792 ▼a2025
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17360108▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
