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A numerical investigation of loss of crack tip constraint in a dynamically loaded ductile specimen

Sumit, Basu and Narasimhan, R (2000) A numerical investigation of loss of crack tip constraint in a dynamically loaded ductile specimen. In: Journal of the Mechanics and Physics of Solids, 48 (9). pp. 1967-1985.

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Abstract

The objectives of this paper are to study the applicability of a two-parameter (J-Q) characterisation of the elastic-plastic crack tip fields in a dynamically loaded ductile specimen and to ascertain the e€ect of loading rate J on the triaxiality parameter Q. To this end, 2D (plane strain) large deformation finite element analyses of a single edge notched specimen (SEN(T)) subjected to a tensile stress pulse are conducted. The material is assumed to obey the $J_2$ flow theory of plasticity with small elastic strains and both rate independent and rate dependent behaviour are considered. The results demonstrate that even a deeply cracked SEN(T) specimen which maintains high triaxiality under quasi-static loading can exhibit progressive loss of triaxiality as the loading rate increases. Since this behaviour is observed for both rate independent and rate dependent case, it is attributed to inertial e€ects. The above phenomenon can satisfactorily explain retarded micro-void growth rates near a notch tip, and strong elevation in the dynamic fracture toughness at high loading rates, which have been reported in recent computational and experimental studies.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier.
Keywords: Elastic-plastic crack tip fields;Constraint loss;Dynamic loading;J-Q locus;Finite elements.
Department/Centre: Division of Mechanical Sciences > Mechanical Engineering
Date Deposited: 10 Aug 2006
Last Modified: 19 Sep 2010 04:30
URI: http://eprints.iisc.ernet.in/id/eprint/8017

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