A multiscale approach for modeling scale-dependent yield stress in polycrystalline metals

Tetsuya Ohashi; Masato Kawamukai; Hussein Zbib

doi:10.1016/j.ijplas.2006.10.002

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A multiscale approach for modeling scale-dependent yield stress in polycrystalline metals

Journal article

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A multiscale approach for modeling scale-dependent yield stress in polycrystalline metals

Tetsuya Ohashi, Masato Kawamukai and Hussein Zbib

International journal of plasticity, Vol.23(5), pp.897-914

2007

DOI: https://doi.org/10.1016/j.ijplas.2006.10.002

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https://hdl.handle.net/2376/108651

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Abstract

A. Dislocations

B. Polycrystalline material

B. Crystal plasticity

B. Scale dependency

B. Constitutive behavior

Modeling of scale-dependent characteristics of mechanical properties of metal polycrystals is studied using both discrete dislocation dynamics and continuum crystal plasticity. The initial movements of dislocation arc emitted from a Frank-Read type dislocation source and bounded by surrounding grain boundaries are examined by dislocation dynamics analyses system and we find the minimum resolved shear stress for the FR source to emit at least one closed loop. When the grain size is large enough compared to the size of FR source, the minimum resolved shear stress levels off to a certain value, but when the grain size is close to the size of the FR source, the minimum resolved shear stress shows a sharp increase. These results are modeled into the expression of the critical resolved shear stress of slip systems and continuum mechanics based crystal plasticity analyses of six-grained polycrystal models are made. Results of the crystal plasticity analyses show a distinct increase of macro- and microscopic yield stress for specimens with smaller mean grain diameter. Scale-dependent characteristics of the yield stress and its relation to some control parameters are discussed.

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Title: A multiscale approach for modeling scale-dependent yield stress in polycrystalline metals
Creators: Tetsuya Ohashi - Kitami Institute of Technology, Koencho 165, Kitami, Hokkaido 090-8507, Japan
Masato Kawamukai - Kitami Institute of Technology, Koencho 165, Kitami, Hokkaido 090-8507, Japan
Hussein Zbib - School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920, USA
Publication Details: International journal of plasticity, Vol.23(5), pp.897-914
Academic Unit: School of Mechanical and Materials Engineering
Publisher: Elsevier Ltd
Identifiers: 99900547153201842
Language: English
Resource Type: Journal article