A fiber toughening model of fiber-reinforced ceramic matrix composites is p
resented. The constitutive equation is obtained through micromechanical con
siderations based on two kinds of fiber toughening mechanisms, crack bridgi
ng and fiber pullout. The calculated results show that two different zones
in the R-curve and Load/displacement curve exhibit notable nonlinear behavi
or. Calculated toughness of 50 vol%SiCf/LAS composites is in good agreement
with experimental results. (C) 1999 Elsevier Science Limited and Techna S.
r.l. All rights reserved.