Steady-state cracking in brittle substrates beneath adherent films

A crack in a brittle substrate parallel to the film/substrate interface is considered. Stress intensity factors are obtained as a function of fiim, substrate thickness, elastic properties and edge loads at arbitrary crack depth. These results, combined with the criterion K 11 = 0. are used to predict the steady-state cracking depth. The critical combination of residual stress and film thickness below which steady-state substrate cracking is avoided can be inferred provided the substrate toughness is known.