NUMERICAL-SIMULATION OF THE INITIATION AND GROWTH OF NEW FATIGUE CRACKS FOLLOWING CRACK INTERSECTIONS

The dual boundary element method has previously been used to analyse c racks in linear elastic materials in two dimensions and to evaluate th e stress intensity factors by contour integrals around the crack tips. In this paper the method is extended to allow new cracks to initiate in response to the sudden increase in the loading coming from stress c oncentrations when existing cracks intersect with boundaries or with e ach other. The sensitivity and stability of the extended procedures ar e examined by their application to the investigation of the growth of cracks within a rectangular plate containing internal holes. The geome tries studied consist of a single primary crack and various arrangemen ts of one to five symmetrically placed circular holes; the plate is lo aded by a uniform normal traction on its ends. The first test, on a si ngle hole intersected by a primary crack, gives good agreement with pr evious results, while simulations with more holes show different regim es of crack initiation and growth in which various numbers of cracks i nitiate, in some cases linking the holes together.