Hhm. Cleveringa et al., COMPARISON OF DISCRETE DISLOCATION AND CONTINUUM PLASTICITY PREDICTIONS FOR A COMPOSITE-MATERIAL, Acta materialia, 45(8), 1997, pp. 3163-3179
Citations number
25
Categorie Soggetti
Material Science","Metallurgy & Metallurigical Engineering
A two-dimensional model composite with elastic reinforcements in a cry
stalline matrix subject to macroscopic shear is analyzed using both di
screte dislocation plasticity and conventional continuum slip crystal
plasticity. In the discrete dislocation formulation, the dislocations
are modeled as line defects in a linear elastic medium. At each stage
of loading, superposition is used to represent the solution in terms o
f the infinite medium solution for the discrete dislocations and a com
plimentary solution that enforces the boundary conditions, which is no
n-singular and obtained from a linear elastic, finite element solution
. The lattice resistance to dislocation motion, dislocation nucleation
, and dislocation annihilation are incorporated into the formulation t
hrough a set of constitutive rules. Obstacles leading to possible disl
ocation pile-ups are also accounted for. Results are presented for mat
erials with a single slip system. A reinforcement size effect is exhib
ited by the discrete dislocation-based analysis whereas the continuum
slip results are size independent. The discrete dislocation results ha
ve higher average reinforcement stress levels than do the correspondin
g continuum slip calculations. Averaging of stress fields over windows
of increasing size is used to gain insight into the transition from d
iscrete dislocation-controlled to continuum behavior. (C) 1997 Acta Me
tallurgica Inc.