NUCLEATION OF MICROCRACKS IN LOCALIZED SLIP BANDS - A DISLOCATION MODEL

Concerning decohesive fracture initiation in coarse localised slip ban ds, the model of Stroh-type blocked array of dislocations is advanced to account for the possibility of separation along a shear plane. Usin g a cohesive force approach, the cores of densely spaced dislocations in a coarse slip band of multiple coplanar pileups are taken into acco unt as the nuclei of both possible traverse and longitudinal cleavages in a band. The equations of equilibrium of this dislocation populatio n in stress field are built up towards establishing the fracture crite ria as the limit conditions of the stability of the band's equilibrium . (C) 1997 Elsevier Science S.A.