A simple micromechanics-based procedure is used to evaluate initial failure maps
for brittle composite laminates under combined in-plane loads and temperature changes.
The maps are derived from local stresses in the fiber, matrix and at their interfaces,
and from selected magnitudes of the respective strengths. In a particular loading plane or
space, the maps indicate the damage-free load range of the laminate, and the source of
likely initial failure by fiber or matrix cracking, or by fiber debonding. An application
to Al2O3/MoSi2 laminates with unidirectional and (0/+/-45)(s) layups is presented.
In this system, the thermal stresses are very small in the 1200 degrees-20 degrees C
range; hence laminate failure is dominated by mechanical loads.
Propensity to fiber debonding appears to limit the load magnitudes that can be safely
applied to the angle-ply laminate.
Last modified: Nov 4 2000