Finite element analyses of the overall stress-strain response of metal
-matrix composites are carried out using axisymmetric and plane strain
unit cell formulations. The metal matrix is characterized as an isotr
opically hardening elastic-plastic solid and the ceramic reinforcement
is taken to be isotropic elastic. Perfect bonding between the matrix
and the reinforcement is assumed. The focus is on the effects of reinf
orcement shape, size and spatial distribution. Under monotonic loading
, the stress-carrying capacity in the plastic range increases in the f
ollowing order for the reinforcement shapes considered: double-cone --
> sphere --> truncated cylinder --> unit cylinder --> whisker. The ext
ent of the Bauschinger effect under reversed loading increases in the
same order for particle reinforced composites. The effects of reinforc
ement size and distribution are analyzed by considering a plane strain
model with two sizes of reinforcing particles. For certain distributi
ons, it is found that the smaller family of particles plays virtually
no role in affecting the stress-strain response. Thermal residual stre
sses are also considered and their effects are seen to persist far int
o the plastic range. The predicted plastic stress-strain behavior can
be rationalized in terms of the evolution of matrix field quantities a
nd, in particular, in terms of the effect of the constraint on plastic
flow.