Analysis of size effect induced by pile-up dislocations using Discrete Dislocation Dynamics, Strain Gradient Plasticity and Field Dislocation Mechanics
Understanding size effects evidenced experimentally in various situations has become one of the hottest issues of the last few years. Many models have been developed to reproduce these size effects. Some are based on generalized continuum mechanics, such as field dislocation mechanics (FDM) [1] and strain gradient plasticity (SGP) [2], and others are directly dealing with dislocations such as discrete dislocation dynamics (DDD) [3]. Generalized continuum mechanics are based on, or related to, geometrically necessary dislocations (GND) and intrinsic length scale concept. In such models, the connection to physical background remains purely phenomenological. On the other hand, DDD can make bridge from the physical origin to the continuum models since it gives access both to GND quantities and to the intrinsic lengths. As an example, Figure shows a typical dislocation microstructure obtained from DDD simulation.
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