An important concern in metalworking is whether the desired deformation can
be accomplished without Failure of the material. This paper describes the
utilisation of ductile fracture criteria in conjunction with the finite ele
ment method for predicting surface and internal failures in cold metalworki
ng processes. Four previously published ductile fracture criteria are selec
ted, and their relative accuracy for predicting and quantifying fracture in
itiation sites is investigated.
Ring, cylindrical, tapered and flanged upset test samples are utilised for
providing the experimental values of the critical damage at fracture under
several different loading conditions.
Two of the ductile fracture criteria are then utilised to predict the initi
ation site and the level of deformation at which surface or internal cracki
ng will occur during finite element simulation of three types of metalworki
ng processes, namely, radial extrusion, open-die forging and blanking. The
analysis is made in conjunction with metal experiments, good agreement bein
g found to occur. (C) 2000 Elsevier Science S.A. All rights reserved.