Inelastic strains due to matrix cracking in unidirectional fiber-reinforced composites

Simulations of the inelastic strains caused by matrix cracking in unidirectional CMCs are performed. They are based on a cell model, which has previously been analyzed by a shear lag approximation. Here, finite element solutions are used to arrive at more accurate formulae, differing from the shear lag results mainly in the range of small debonds. The model relates the inelastic strain to the constitutive properties, particularly the interface sliding and debonding resistances. Comparisons with experimental results indicate good correspondence for a SiC/SiC composite but divergences for a SiC/CAS composite. The divergences are attributed to the contribution of inelastic strain from fiber failure.