Volume 38 Issue 3
Feb 2022
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J. Zhao, B. Zhang, D. Liu, A. A. Konstantinidis, G. Kang, and X. Zhang,Generalized Aifantis strain gradient plasticity model with internal length scale dependence on grain size, sample size and strain. Acta Mech. Sin., 2022, 38, http://www.w3.org/1999/xlink' xlink:href='https://doi.org/10.1007/s10409-022-09009-2'>https://doi.org/10.1007/s10409-022-09009-2
Citation: J. Zhao, B. Zhang, D. Liu, A. A. Konstantinidis, G. Kang, and X. Zhang,Generalized Aifantis strain gradient plasticity model with internal length scale dependence on grain size, sample size and strain. Acta Mech. Sin., 2022, 38, http://www.w3.org/1999/xlink" xlink:href="https://doi.org/10.1007/s10409-022-09009-2">https://doi.org/10.1007/s10409-022-09009-2

Generalized Aifantis strain gradient plasticity model with internal length scale dependence on grain size, sample size and strain

doi: 10.1007/s10409-022-09009-2
Funds:

the National Natural Science Foundation of China Grant

More Information
  • Corresponding author: Zhang Xu, E-mail address: xzhang@swjtu.edu.cn (Xu Zhang)
  • Accepted Date: 02 Nov 2021
  • Available Online: 01 Aug 2022
  • Publish Date: 01 Mar 2022
  • Issue Publish Date: 01 Mar 2022
  • The internal length scale (ILS) is a dominant parameter in strain gradient plasticity (SGP) theories, which helps to successfully explain the size effect of metals at the microscale. However, the ILS is usually introduced into strain gradient frameworks for dimensional consistency and is model-dependent. Even now, its physical meaning, connection with the microstructure of the material, and dependence on the strain level have not been thoroughly elucidated. In the current work, Aifantis’ SGP model is reformulated by incorporating a recently proposed power-law relation for strain-dependent ILS. A further extension of Aifantis’ SGP model by including the grain size effect is conducted according to the Hall-Petch formulation, and then the predictions are compared with torsion experiments of thin wires. It is revealed that the ILS depends on the sample size and grain size simultaneously; these dependencies are dominated by the dislocation spacing and can be well described through the strain hardening exponent. Furthermore, both the original and generalized Aifantis models provide larger estimated values for the ILS than Fleck-Hutchinson’s theory.

     

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