MICROMECHANICS MODEL FOR PREDICTING THE TENSILE STRENGTH OF
UNIDIRECTIONAL METAL MATRIX COMPOSITES
this paper, a micromechanics model has been developed to predict
the tensile strength of unidirectional metal matrix composites
(MMC). A simplified shear lag analysis is used to estimate the
local stresses in the various constituents (fiber/matrix/interface).
In this work, the matrix is assumed to carry both normal and
shear stresses. Global matrix plasticity is considered by assuming
that the matrix behaves in an elastic-perfectly plastic manner.
Local interfacial debonding is assumed to occur when the average
interfacial shear stress exceeds the interfacial shear strength
value. The shear lag analysis including the effects of interfacial
debonding and global matrix plasticity is used to estimate the
stress concentration in fibers adjacent to broken fibers and
the ineffective length. The tensile strength is estimated by
considering the accumulation of fiber fractures. The effects
of residual thermal stresses and statistical distribution of
strength of the fibers are also included in this analysis.
studies were conducted to investigate the influence of various
parameters such as fiber volume fraction, temperature, interfacial
shear strength, matrix properties and fiber strength, on the
unidirectional tensile strength of MMC. The model was also used
to predict the effects of volume fraction and temperature, on
the strength of SCS6/Ti 24-11 composites. The predicted values
compared well with the experimental results.