Modeling damage and fracture within strain-gradient plasticity

Steady-state Crack Growth and Work of Fracture for Solids Characterized by Strain Gradient Plasticity

Mode I steady-state crack growth is analysed under plane strain conditions in small scale yielding. The elastic-plastic solid is characterized by a generalization of JZ flow theory which accounts for the influence of the gradients of plastic strains on hardening. The constitutive model involves one new parameter, a material length 1, specifying the scale of nonuniform deformation at which harde...

A Variational Framework for Gradient-Extended Dissipative Continua. Application to Damage Mechanics, Fracture, and Plasticity

Strain gradient plasticity under non-proportional loading

A critical examination is made of two classes of strain gradient plasticity theories currently available for studying micrometre-scale plasticity. One class is characterized by certain stress quantities expressed in terms of increments of strains and their gradients, whereas the other class employs incremental relationships between all stress quantities and the increments of strains and their g...

Guidelines for Constructing Strain Gradient Plasticity Theories

Issues related to the construction of continuum theories of strain gradient plasticity which have emerged in recent years are reviewed and brought to bear on the formulation of the most basic theories. Elastic loading gaps which can arise at initial yield or under imposition of non-proportional incremental boundary conditions are documented and analytical methods for dealing with them are illus...

Fracture analysis in the conventional theory of mechanism-based strain gradient (CMSG) plasticity

In a remarkable series of experiments, Elssner et al. (1994) and Korn et al. (2002) observed cleavage cracking along a bimaterial interface between Nb and sapphire. The stress required for cleavage cracking is around the theoretical strength of the material. Classical plasticity models fall short to reach such a high stress level. We use the conventional theory of mechanism-based strain gradien...