Characterization of fracture loci in metal forming

Fracture in metal forming can occur in three different modes: (i) tensile; (ii) in-plane shear; and (iii) out-of-plane shear (respectively the same as modes 1, II and III of fracture mechanics). The circumstances under which each mode will occur are identified in terms of plastic flow and microstructural ductile damage by means of an analytical framework to characterize fracture loci under plane stress conditions that also takes anisotropy into consideration. Experimental results retrieved from the literature give support to the presentation and show that plastic flow and failure in sheet forming results from competition between modes I and II whereas in bulk forming fracture results from competition between modes I and III. (C) 2014 Elsevier Ltd. All rights reserved.