Crack tip strain evolution and crack closure during overload of a growing fatigue crack
It is generally accepted that fatigue crack growth is retarded after an overload, which has been explained either by plasticity-induced crack closure or near-tip residual stress. However, any interpretation of overload effect is insufficient if strain evolution in front of crack tip is not properly...
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| Format: | Article |
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Gruppo Italiano Frattura
2017-07-01
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| Series: | Fracture and Structural Integrity |
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| Online Access: | http://www.gruppofrattura.it/pdf/rivista/numero41/numero_41_art_20.pdf |
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| _version_ | 1846145585715871744 |
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| author | De-Qiang Wang Ming-Liang Zhu Fu-Zhen Xuan Jie Tong |
| author_facet | De-Qiang Wang Ming-Liang Zhu Fu-Zhen Xuan Jie Tong |
| author_sort | De-Qiang Wang |
| collection | DOAJ |
| description | It is generally accepted that fatigue crack growth is retarded after an overload, which has been explained either by plasticity-induced crack closure or near-tip residual stress. However, any interpretation of overload effect is insufficient if strain evolution in front of crack tip is not properly considered. The current understanding of overload-induced retardation lacks the clarification of the relationship between crack closure at crack wake and strain evolution at crack tip. In this work, a material with low work hardening coefficient was used to study the effect of overload on crack tip strain evolution and crack closure by in-situ SEM observation and digital image correlation technique. Crack opening displacement (COD) and crack tip strain were measured before and after the overload. It was observed that the evolution of crack tip strain follows the crack opening behaviour behind the crack tip, indicating a smaller influence of overload on micro-mechanical behaviour of fatigue crack growth. After the overload, plastic strain accumulation was responsible for crack growth. The strain at a certain distance to crack tip was mapped, and it was found that the crack tip plastic zone size correlated well with crack growth rate during post-overload fatigue crack propagation. |
| format | Article |
| id | doaj-art-17208dd17eeb45f28d967b07fc48e091 |
| institution | Kabale University |
| issn | 1971-8993 1971-8993 |
| language | English |
| publishDate | 2017-07-01 |
| publisher | Gruppo Italiano Frattura |
| record_format | Article |
| series | Fracture and Structural Integrity |
| spelling | doaj-art-17208dd17eeb45f28d967b07fc48e0912024-12-02T05:47:01ZengGruppo Italiano FratturaFracture and Structural Integrity1971-89931971-89932017-07-01114114314810.3221/IGF-ESIS.41.20Crack tip strain evolution and crack closure during overload of a growing fatigue crackDe-Qiang Wang0Ming-Liang Zhu1Fu-Zhen Xuan 2Jie Tong 3East China University of Science & Technology, Shanghai, China East China University of Science & Technology, Shanghai, China East China University of Science & Technology, Shanghai, China University of Portsmouth, UK It is generally accepted that fatigue crack growth is retarded after an overload, which has been explained either by plasticity-induced crack closure or near-tip residual stress. However, any interpretation of overload effect is insufficient if strain evolution in front of crack tip is not properly considered. The current understanding of overload-induced retardation lacks the clarification of the relationship between crack closure at crack wake and strain evolution at crack tip. In this work, a material with low work hardening coefficient was used to study the effect of overload on crack tip strain evolution and crack closure by in-situ SEM observation and digital image correlation technique. Crack opening displacement (COD) and crack tip strain were measured before and after the overload. It was observed that the evolution of crack tip strain follows the crack opening behaviour behind the crack tip, indicating a smaller influence of overload on micro-mechanical behaviour of fatigue crack growth. After the overload, plastic strain accumulation was responsible for crack growth. The strain at a certain distance to crack tip was mapped, and it was found that the crack tip plastic zone size correlated well with crack growth rate during post-overload fatigue crack propagation.http://www.gruppofrattura.it/pdf/rivista/numero41/numero_41_art_20.pdfIn-situ SEMOverloadFatigue crack growthDigital image correlation |
| spellingShingle | De-Qiang Wang Ming-Liang Zhu Fu-Zhen Xuan Jie Tong Crack tip strain evolution and crack closure during overload of a growing fatigue crack Fracture and Structural Integrity In-situ SEM Overload Fatigue crack growth Digital image correlation |
| title | Crack tip strain evolution and crack closure during overload of a growing fatigue crack |
| title_full | Crack tip strain evolution and crack closure during overload of a growing fatigue crack |
| title_fullStr | Crack tip strain evolution and crack closure during overload of a growing fatigue crack |
| title_full_unstemmed | Crack tip strain evolution and crack closure during overload of a growing fatigue crack |
| title_short | Crack tip strain evolution and crack closure during overload of a growing fatigue crack |
| title_sort | crack tip strain evolution and crack closure during overload of a growing fatigue crack |
| topic | In-situ SEM Overload Fatigue crack growth Digital image correlation |
| url | http://www.gruppofrattura.it/pdf/rivista/numero41/numero_41_art_20.pdf |
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