Abstract
In this paper, the effect of plastic constraint on the initiation of ductile tears in four different shipbuilding structural steels has been experimentally studied by measuring the J-integral and crack opening displacement COD at initiation in three-point bend specimens with deep and shallow notches. Experimental results of seven groups of different strength alloy steels show that both δi and Jì values of ductile tear from the shallow crack specimens which have less constraint flow field are significantly higher than those of deeply notched specimens. Slip-line-field analysis shows that, for shallow crack, the hydrostatic stress is lower than that from standard deeply cracked bend specimen, which develops a high level of crack tip constraint, provides a lower bound estimate of toughness, and will ensure an unduly conservative approach when applied to structural defects, especially if initiation values of COD and J-integral are used.
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LI Qing-fen (1944 –) graduated in Aeronautical Engineering from Harbin Military Engineering Institute in 1968. She is a Professor and supervisor for PHD students in College of Mechanical & Electrical Engineering, Harbin Engineering University, China. She had been a Visiting Scholar in the Department of Mechanical Engineering, University of Sydney, N.S.W., Australia from 1980–1982, and Visiting Professor in the Department of Mechanical Engineering, University of Glasgow, Scotland, U. K. in 1996. She is a member of Directorate of Modern Design Theory and Method Committee of China. She has authored and co-authored 126 papers in national and international journals, books and conference proceedings (48 papers were covered by SCI, EI and ISTP), including eleven books. She has obtained three Second Class and two Third Class Awards of Science and Technology Advancement. Her research interests are in machine design, fracture mechanics, materials strength and materials design.
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Li, Qf., Wang, P., Ren, Zy. et al. The effect of plastic constraint on the initiation of ductile tears in shipbuilding structural steels. J. Marine. Sci. Appl. 2, 1–4 (2003). https://doi.org/10.1007/BF02918656
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DOI: https://doi.org/10.1007/BF02918656