منابع مشابه
Pile - up studies in dislocation - based single crystal gradient plasticity
/department of mechanical engineering Introduction In plastic deformations, which arise due to the motion of dislocations in crystalline microstructure, size effects cannot be neglected at a small scales of observation. Within each grain of a polycrystal, the grain boundaries act as natural obstacles to dislocation motion. Due to the stresses dislocations exert onto each other, dislocations wil...
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We consider the variational formulation of both geometrically linear and geometrically nonlinear elasto-plasticity subject to a class of hard single-slip conditions. Such side conditions typically render the associated boundary-value problems non-convex. We show that, for a large class of non-smooth plastic distortions, a given single-slip condition (specification of Burgers vectors) can be rel...
متن کاملGradient plasticity in gradient nano-grained metals
Gradient nano-grained (GNG) metals are a unique class of materials with spatial gradients in grain size, typically from the surface to the bulk. Here the gradient mechanical behavior inGNG copper is studied by a crystal plasticity finite elementmodel that accounts for grainsize-dependent yield strengths. The associated finite element simulations reveal both the gradient stress and gradient plas...
متن کاملGuidelines 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...
متن کاملFinite Element Analysis and Algorithms for Single-Crystal Strain-Gradient Plasticity
We provide optimal a priori estimates for nite element approximations of a model of rate-independent single-crystal strain-gradient plasticity. The weak formulation of the problem takes the form of a variational inequality in which the primary unknowns are the displacement and slips on the prescribed slip systems, as well as the back-stress associated with the vectorial microstress. It is shown...
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ژورنال
عنوان ژورنال: PAMM
سال: 2010
ISSN: 1617-7061
DOI: 10.1002/pamm.201010168