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Quasi-static crack tip fields in rate-sensitive FCC single crystals

Biswas, P and Narasimhan, R (2012) Quasi-static crack tip fields in rate-sensitive FCC single crystals. In: SADHANA-ACADEMY PROCEEDINGS IN ENGINEERING SCIENCES, 37 (1, SI). pp. 149-169.

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Abstract

In this work, the effects of loading rate, material rate sensitivity and constraint level on quasi-static crack tip fields in a FCC single crystal are studied. Finite element simulations are performed within a mode I, plane strain modified boundary layer framework by prescribing the two term (K-T) elastic crack tip field as remote boundary conditions. The material is assumed to obey a rate-dependent crystal plasticity theory. The orientation of the single crystal is chosen so that the crack surface coincides with the crystallographic (010) plane and the crack front lies along 101] direction. Solutions corresponding to different stress intensity rates K., T-stress values and strain rate exponents m are obtained. The results show that the stress levels ahead of the crack tip increase with K. which is accompanied by gradual shrinking of the plastic zone size. However, the nature of the shear band patterns around the crack tip is not affected by the loading rate. Further, it is found that while positive T-stress enhances the opening and hydrostatic stress levels ahead of crack tip, they are considerably reduced with imposition of negative T-stress. Also, negative T-stress promotes formation of shear bands in the forward sector ahead of the crack tip and suppresses them behind the tip.

Item Type: Journal Article
Additional Information: Copyright for this article belongs the Indian Academy of Sciences
Keywords: Rate sensitivity;crack tip constraint;quasi-static fields; crystal plasticity;finite elements
Department/Centre: Division of Mechanical Sciences > Mechanical Engineering
Date Deposited: 18 Jul 2012 11:57
Last Modified: 18 Jul 2012 11:58
URI: http://eprints.iisc.ernet.in/id/eprint/44548

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