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A variational multiscale constitutive model for nanocrystalline materials
Date
2011-03-01
Author
Gürses, Ercan
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This paper presents a variational multi-scale constitutive model in the finite deformation regime capable of capturing the mechanical behavior of nanocrystalline (nc) fcc metals. The nc-material is modeled as a two-phase material consisting of a grain interior phase and a grain boundary effected zone (GBAZ). A rate-independent isotropic porous plasticity model is employed to describe the GBAZ, whereas a crystal-plasticity model which accounts for the transition from partial dislocation to full dislocation mediated plasticity is employed for the grain interior. The constitutive models of both phases are formulated in a small strain framework and extended to finite deformation by use of logarithmic and exponential mappings. Assuming the rule of mixtures, the overall behavior of a given grain is obtained via volume averaging. The scale transition from a single grain to a polycrystal is achieved by Taylor-type homogenization where a log-normal grain size distribution is assumed. It is shown that the proposed model is able to capture the inverse Hall-Perch effect, i.e., loss of strength with grain size refinement. Finally, the predictive capability of the model is validated against experimental results on nanocrystalline copper and nickel.
Subject Keywords
Mechanical Engineering
,
Mechanics of Materials
,
Condensed Matter Physics
URI
https://hdl.handle.net/11511/39978
Journal
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
DOI
https://doi.org/10.1016/j.jmps.2010.10.010
Collections
Department of Aerospace Engineering, Article
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E. Gürses, “A variational multiscale constitutive model for nanocrystalline materials,”
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
, pp. 732–749, 2011, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39978.