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The problem of mixed-mode fatigue crack growth has been a persistent research challenge. The determination of fatigue crack propagation direction directly impacts the safety and integrity of components and structures, making it crucial in various industrial applications, including welded drilling pi...
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| Format: | Thesis |
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AUC Knowledge Fountain
2027
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| _version_ | 1869483686217383936 |
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| access_status_str | Open Access |
| author | Matar, Nahla Helmy |
| author_browse | Matar, Nahla Helmy |
| author_facet | Matar, Nahla Helmy |
| author_sort | Matar, Nahla Helmy |
| collection | Thesis |
| description | The problem of mixed-mode fatigue crack growth has been a persistent research challenge. The determination of fatigue crack propagation direction directly impacts the safety and integrity of components and structures, making it crucial in various industrial applications, including welded drilling pipes, aerospace, and automotive engineering. Unlike uniaxial loading, mixed-mode cracks tend to change direction frequently (kinking), and nonproportional loading adds to the complexity of the problem. This research aims to estimate the crack propagation direction and fatigue crack life in linear elastic materials subjected to mixed-mode (I+II) loading conditions under proportional or non-proportional cyclic loading. Numerical software was developed based on the Maximum Energy Release Rate (MERR) approach, which offers many advantages over other crack propagation criteria. The crack propagation path in a thin-walled cylinder subjected to axial and torsional fatigue loading is investigated. The loading phase difference ranged from 0° (proportional) to nonproportional phase angles up to 90°. The model simulates crack propagation in small increments over angles from 0° to 360°, and the energy release rate is calculated at each angle. The angle at which the crack releases the maximum energy is taken as the crack's direction. Results from the numerical simulations were validated against experimental and finite element data from the literature and compared with prior studies, proving good agreement with all. |
| format | Thesis |
| id | oai:fount.aucegypt.edu:etds-3884 |
| institution | American University in Cairo (Egypt) |
| last_indexed | 2026-07-01T04:02:56.486Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from AUC Knowledge Fountain — bepress |
| publishDate | 2027 |
| publishDateRange | 2027 |
| publishDateSort | 2027 |
| publisher | AUC Knowledge Fountain |
| publisherStr | AUC Knowledge Fountain |
| record_format | dspace |
| source_str | AUC Knowledge Fountain — bepress |
| spelling | oai:fount.aucegypt.edu:etds-3884 A Maximum Energy Release Rate Computational Framework for Fatigue Crack Trajectory and Life Prediction under Mixed-Mode Proportional and Nonproportional Loading Matar, Nahla Helmy The problem of mixed-mode fatigue crack growth has been a persistent research challenge. The determination of fatigue crack propagation direction directly impacts the safety and integrity of components and structures, making it crucial in various industrial applications, including welded drilling pipes, aerospace, and automotive engineering. Unlike uniaxial loading, mixed-mode cracks tend to change direction frequently (kinking), and nonproportional loading adds to the complexity of the problem. This research aims to estimate the crack propagation direction and fatigue crack life in linear elastic materials subjected to mixed-mode (I+II) loading conditions under proportional or non-proportional cyclic loading. Numerical software was developed based on the Maximum Energy Release Rate (MERR) approach, which offers many advantages over other crack propagation criteria. The crack propagation path in a thin-walled cylinder subjected to axial and torsional fatigue loading is investigated. The loading phase difference ranged from 0° (proportional) to nonproportional phase angles up to 90°. The model simulates crack propagation in small increments over angles from 0° to 360°, and the energy release rate is calculated at each angle. The angle at which the crack releases the maximum energy is taken as the crack's direction. Results from the numerical simulations were validated against experimental and finite element data from the literature and compared with prior studies, proving good agreement with all. 2027-01-31T08:00:00Z dissertation application/pdf https://fount.aucegypt.edu/etds/2819 https://fount.aucegypt.edu/context/etds/article/3884/viewcontent/Nahla_Helmy_Matar_Thesis.pdf Theses and Dissertations AUC Knowledge Fountain Solid Mechanics fracture Mechanics Fatigue Nonproportional Fatigue Life Crack propagation Applied Mechanics Computer-Aided Engineering and Design Structural Materials |
| spellingShingle | Solid Mechanics fracture Mechanics Fatigue Nonproportional Fatigue Life Crack propagation Applied Mechanics Computer-Aided Engineering and Design Structural Materials Matar, Nahla Helmy A Maximum Energy Release Rate Computational Framework for Fatigue Crack Trajectory and Life Prediction under Mixed-Mode Proportional and Nonproportional Loading |
| title | A Maximum Energy Release Rate Computational Framework for Fatigue Crack Trajectory and Life Prediction under Mixed-Mode Proportional and Nonproportional Loading |
| title_full | A Maximum Energy Release Rate Computational Framework for Fatigue Crack Trajectory and Life Prediction under Mixed-Mode Proportional and Nonproportional Loading |
| title_fullStr | A Maximum Energy Release Rate Computational Framework for Fatigue Crack Trajectory and Life Prediction under Mixed-Mode Proportional and Nonproportional Loading |
| title_full_unstemmed | A Maximum Energy Release Rate Computational Framework for Fatigue Crack Trajectory and Life Prediction under Mixed-Mode Proportional and Nonproportional Loading |
| title_short | A Maximum Energy Release Rate Computational Framework for Fatigue Crack Trajectory and Life Prediction under Mixed-Mode Proportional and Nonproportional Loading |
| title_sort | maximum energy release rate computational framework for fatigue crack trajectory and life prediction under mixed mode proportional and nonproportional loading |
| topic | Solid Mechanics fracture Mechanics Fatigue Nonproportional Fatigue Life Crack propagation Applied Mechanics Computer-Aided Engineering and Design Structural Materials |
| url | https://fount.aucegypt.edu/etds/2819 https://fount.aucegypt.edu/context/etds/article/3884/viewcontent/Nahla_Helmy_Matar_Thesis.pdf |
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