Fracture mechanics of specially orthotropic shells containing a crack.

This article presents a theoretical analysis of specially-orthotropic shells containing a crack in terms of a crack-closure theory. The formulation of Delale and Erdogan for crack problems in shells is extended to include the effect of crack-face closure. The influence of material orthotropy and shell curvatures on the closure behaviour and consequently on the stress intensity factor are studied. It is demonstrated that crack-face closure has a significant impact on the stress intensity factor and it tends to reduce the maximum stress intensity factor. The crack-face closure effect on the stress intensity factor increases with the shell radii. In flat plates, as a special case of shells when the shell radii become infinitely large, the difference of the closure stress intensity factor between the closure case and non-closure case has a maximum. The influence of material orthotropy on the closure behaviour varies with the ratio of the two shell curvatures. [ABSTRACT FROM PUBLISHER]