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Modeling dislocation
sources and size effects at initial yield in continuum
plasticity
Saurabh Puri, Anish Roy, Amit Acharya and Dennis Dimiduk |
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Vol. 4 (2009), No. 9, 1603–1618
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Abstract |
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Size effects at initial yield (prior to stage II) of idealized micron-sized specimens are modeled within a continuum model of plasticity. Two different aspects are considered: specification of a density of dislocation sources that represent the emission of dislocation dipoles, and the presence of an initial, spatially inhomogeneous excess dislocation content. Discreteness of the source distribution appears to lead to a stochastic response in stress-strain curves, with the stochasticity diminishing as the number of sources increases. Variability in stress-strain response due to variations of source distribution is also shown. These size effects at initial yield are inferred to be due to physical length scales in dislocation mobility and the discrete description of sources that induce internal-stress-related effects, and not due to length-scale effects in the mean-field strain-hardening response (as represented through a constitutive equation). |
Keywords
continuum plasticity, dislocations, finite elements
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Milestones
Received: 16 July 2008
Revised: 14 March 2009
Accepted: 4 June 2009
Published: 17 January 2010
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Authors |
| Saurabh Puri | |
| Department of Mechanical
Engineering California Institute of Technology Pasadena, CA 91125 United States |
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| Anish Roy | |
| Wolfson School of Mechanical and
Manufacturing Engineering Loughborough University Leicestershire, LE11 3TU United Kingdom |
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| Amit Acharya | |
| Department of Civil and
Environmental Engineering Carnegie Mellon University Pittsburgh, PA 15213 United States |
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| Dennis Dimiduk | |
| Air Force Research Laboratory Materials and Manufacturing Directorate AFRL/MLLM Bldg. 655 2230 Tenth Street Wright-Patterson AFB, OH 45433-7817 United States |
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