The primary objective of the present study is to show that in many practical cases of free surface fracture, the modified Cockroft—Latham ductile fracture criterion is reduced to a relation between two in-surface principal strains. This finding can be combined with an appropriate set of experimental data to determine the input parameter of the criterion and/or verify it. An illustrative example is provided.
AtkinsA. G.Fracture in forming. J. Mater. Process. Technol.199656(1-4)609–618.
2.
ShabaraM. A.El-DomiatyA. A.KandilM. A.Validity assessment of ductile fracture criteria in cold forming. J. Mater. Eng. Perform.19965(4)478–488.
3.
HambliR.ReszkaM.Fracture criteria identification using an inverse technique method and blanking experiment. Int. J. Mech. Sci.2002441349–1361.
4.
BehrensA.JustH.Verification of the damage model of effective stresses in cold and warm forging operations by experimental testing and FE simulations. J. Mater. Process. Technol.2002125-126295–301.
5.
RoweG. M.SturgessC. E. N.HartleyP.PillingerI.Finite-element plasticity and metal forming analysis1991 (Cambridge University PressCambridge, UK).
6.
ViloticD.PlancakM.GrbicS.AlexandrovS.ChikanovaN.An approach to determining the workability diagram based on upsetting tests. Fat. Fract. Eng. Mater. Struct.200326(4)305–310.
7.
ViloticD.PlanchakM.ChupkovichD.AlexandrovS.AlexandrovaN.Free surface fracture in three upsetting tests. Expl Mech.200646(1)115–120.
8.
OhS. I.ChenC. C.KobayashiS.Ductile fracture in axisymmetric extrusion and drawing. Part 2: Workability in extrusion and drawing. ASME J. Eng. Ind.197910136–44.
9.
CockroftM. D.LathamD. J.Ductility and the workability of metals. J. Inst. Metals19689633–39.
10.
OgawaN.ShiomiM.OsakadaK.Forming limit of magnesium alloy at elevated temperatures for forging. Int. J. Mach. Tools Manuf.200242607–614.
11.
SljapicV.HartleyP.PillingerI.Observations on fracture in axi-symmetric and three-dimensional cold upsetting of brass. J. Mater. Process. Technol.2002125-126267–274.
