Details

Autor(en) / Beteiligte

• Ryś, M.
• Forest, S.
• Petryk, H.

Titel

A micromorphic crystal plasticity model with the gradient-enhanced incremental hardening law

Ist Teil von

• International journal of plasticity, 2020-05, Vol.128, p.102655, Article 102655

Ort / Verlag

New York: Elsevier Ltd

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• A model of crystal plasticity is developed in which the effects of plastic flow non-uniformity are described through the full dislocation density tensor. The micromorphic approach is used in which the dislocation density tensor is represented by the curl of an independent constitutive variable called microdeformation. The microdeformation tensor is enforced by an energetic penalty term to be close to the actual plastic distortion tensor. The curl of microdeformation tensor enters the constitutive model in two independent but complementary ways. First, it is an argument of the free energy density function, which describes the kinematic-type hardening in cyclic non-uniform deformation. Second, its rate influences the rates of critical resolved shear stresses, which corresponds to additional isotropic hardening caused by incompatibility of the plastic flow rate. The latter effect, missing in the standard slip-system hardening rule, is described in a simple manner that does not require any extra parameter in comparison to the non-gradient theory. In the proposed model there are two independent internal length scales whose interplay is examined by means of 1D and 2D numerical examples of plastic shearing of a single crystal. •Micromorphic approach to gradient plasticity of single crystals is developed.•Interaction of two distinct effects of plastic flow non-uniformity is examined.•The full dislocation density tensor is approximated by a micromorphic variable.•Its curl projected on a slip-system defines an energetic back-stress.•Curl of the rate of micromorphic variable affects the incremental hardening law.