A class of rate-independent lower-order gradient plasticity theories: Implementation and application to disc torsion problem

Emin Semih Perdahcioğlu* (Corresponding Author), Celal Soyarslan, Emin Erkan Asik, Ton van den Boogaard, Swantje Bargmann

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    2 Citations (Scopus)
    88 Downloads (Pure)

    Abstract

    As the characteristic scale of products and production processes decreases, the plasticity phenomena observed start to deviate from those evidenced at the macroscale. The current research aims at investigating this gap using a lower-order gradient enhanced approach both using phenomenological continuum level as well as crystal plasticity models. In the phenomenological approach, a physically based hardening model relates the flow stress to the density of dislocations where it is assumed that the sources of immobile dislocations are both statistically stored (SSDs) as well as geometrically necessary dislocations (GNDs). In the crystal plasticity model, the evolution of the critical resolved shear stress is also defined based on the total number of dislocations. The GNDs are similarly incorporated in the hardening based on projecting the plastic strain gradients through the Burgers tensor on slip systems. A rate-independent formulation is considered that eliminates any artificial inhomogeneous hardening behavior due to numerical stabilization. The behavior of both models is compared in simulations focusing on the effect of structurally imposed gradients versus the inherent gradients arising in crystal plasticity simulations.

    Original languageEnglish
    Article number1425
    JournalMaterials
    Volume11
    Issue number8
    DOIs
    Publication statusPublished - 14 Aug 2018

    Keywords

    • Crystal plasticity
    • GND
    • Size dependence
    • SSD
    • Strain gradient

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