Treating internal surfaces and interfaces in discrete dislocation dynamics
The treatment of coherent interfaces and cracks is discussed in the framework of dislocation dynamics (DD). In the case of interfaces, we use DD to study dislocation interactions in nanoscale bimetallic laminates, and to predict their structure after relaxation and during loading. In agreement with...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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De Gruyter
2011-12-01
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| Series: | Journal of the Mechanical Behavior of Materials |
| Subjects: | |
| Online Access: | https://doi.org/10.1515/JMBM.2011.002 |
| _version_ | 1818356049656152064 |
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| author | Mastorakos Ioannis N. Akasheh Firas E. Zbib Hussein M. |
| author_facet | Mastorakos Ioannis N. Akasheh Firas E. Zbib Hussein M. |
| author_sort | Mastorakos Ioannis N. |
| collection | DOAJ |
| description | The treatment of coherent interfaces and cracks is discussed in the framework of dislocation dynamics (DD). In the case of interfaces, we use DD to study dislocation interactions in nanoscale bimetallic laminates, and to predict their structure after relaxation and during loading. In agreement with experimental observations, our discrete dynamics simulations show that dislocation structure develops only at the interface between coherent layers leaving layers’ interior dislocation-free. The main dislocation mechanism at this length scale is Oworan bowing of threading dislocations confined to their respective layers by the sign-alternating coherency stress field in the layers. Slip transmission across the interfaces marks the end of the confined slip regime, hence, the breakdown of the interfaces and macroscopic yielding of these structures. In the case of crack, its long-range and singular stress field is determined by modeling the crack as continuous distribution of dislocation loops. The traction boundary condition to be satisfied at the crack surface, results into a singular integral equation of the first kind that is solved numerically. The model is integrated with the DD technique to investigate the behavior of a specimen containing cracks of different shapes under fatigue. The results are compared with the behavior of an uncracked specimen and conclusions are extracted. Extension of this crack treatment methodology to account for their presence at interfaces, all within the frame dislocations dynamics, opens the door for a more realistic approach to a wide range of interfaces-related problems. |
| first_indexed | 2024-12-13T19:51:02Z |
| format | Article |
| id | doaj.art-d42fc76700d348d98a725b3acb843e82 |
| institution | Directory Open Access Journal |
| issn | 0334-8938 2191-0243 |
| language | English |
| last_indexed | 2024-12-13T19:51:02Z |
| publishDate | 2011-12-01 |
| publisher | De Gruyter |
| record_format | Article |
| series | Journal of the Mechanical Behavior of Materials |
| spelling | doaj.art-d42fc76700d348d98a725b3acb843e822022-12-21T23:33:26ZengDe GruyterJournal of the Mechanical Behavior of Materials0334-89382191-02432011-12-01201-3132010.1515/JMBM.2011.002Treating internal surfaces and interfaces in discrete dislocation dynamicsMastorakos Ioannis N.0Akasheh Firas E.1Zbib Hussein M.2School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USAMechanical Engineering, Tuskegee University, Tuskegee, AL 36088, USASchool of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164, USAThe treatment of coherent interfaces and cracks is discussed in the framework of dislocation dynamics (DD). In the case of interfaces, we use DD to study dislocation interactions in nanoscale bimetallic laminates, and to predict their structure after relaxation and during loading. In agreement with experimental observations, our discrete dynamics simulations show that dislocation structure develops only at the interface between coherent layers leaving layers’ interior dislocation-free. The main dislocation mechanism at this length scale is Oworan bowing of threading dislocations confined to their respective layers by the sign-alternating coherency stress field in the layers. Slip transmission across the interfaces marks the end of the confined slip regime, hence, the breakdown of the interfaces and macroscopic yielding of these structures. In the case of crack, its long-range and singular stress field is determined by modeling the crack as continuous distribution of dislocation loops. The traction boundary condition to be satisfied at the crack surface, results into a singular integral equation of the first kind that is solved numerically. The model is integrated with the DD technique to investigate the behavior of a specimen containing cracks of different shapes under fatigue. The results are compared with the behavior of an uncracked specimen and conclusions are extracted. Extension of this crack treatment methodology to account for their presence at interfaces, all within the frame dislocations dynamics, opens the door for a more realistic approach to a wide range of interfaces-related problems.https://doi.org/10.1515/JMBM.2011.002cracksdislocation dynamicsnanomaterials |
| spellingShingle | Mastorakos Ioannis N. Akasheh Firas E. Zbib Hussein M. Treating internal surfaces and interfaces in discrete dislocation dynamics Journal of the Mechanical Behavior of Materials cracks dislocation dynamics nanomaterials |
| title | Treating internal surfaces and interfaces in discrete dislocation dynamics |
| title_full | Treating internal surfaces and interfaces in discrete dislocation dynamics |
| title_fullStr | Treating internal surfaces and interfaces in discrete dislocation dynamics |
| title_full_unstemmed | Treating internal surfaces and interfaces in discrete dislocation dynamics |
| title_short | Treating internal surfaces and interfaces in discrete dislocation dynamics |
| title_sort | treating internal surfaces and interfaces in discrete dislocation dynamics |
| topic | cracks dislocation dynamics nanomaterials |
| url | https://doi.org/10.1515/JMBM.2011.002 |
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