PREDICTION OF EDGE STRESSES IN LAYERED MEDIA USING THE SURFACE INTEGRAL-FINITE ELEMENT TECHNIQUE

A method for predicting the state of stress in a finite body consisting of two isotropic material layers, including a characterization of the singular stress state at the intersection of the interface with a stress-free boundary, is presented. The prediction of the ''free edge stress'' is accomplished using elastic stress intensity parameters. Arbitrary two-dimensional geometries with mechanical and thermal loading and plane strain or plane stress behavior are addressed. The approach consists of coupling the finite element solution of two unattached layers to a singular integral representation of distributed dislocations along the interface of two semi-infinite layers. Coupling of the two methods occurs along the interface, where displacement compatibility is enforced, and at the finite boundary, where correction forces are defined to eliminate the tractions from the semi-infinite dislocation solution. The stress intensity factors at the free edge interface are derived from the singular integral solution.