TOUGHNESS OF DAMAGE-TOLERANT CONTINUOUS FIBER-REINFORCED CERAMIC-MATRIX COMPOSITES

A simple shear-lag model is used to estimate the toughness of a unidir ectional fibre reinfored ceramic matrix composite. In the model, which includes the residual axial stresses, the stress transfer across the fibre/matrix interface is by a constant shear stress. The estimates fr om the model are compared to experimental measurements for four compos ites and good agreement is found. The effects of distributed and local ized energy uptake on fracture stability are discussed and it is concl uded that for most applications the toughness, rather than the pull-ou t energy absorption, should be maximized.