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Frontiers of Mechanical Engineering

ISSN 2095-0233

ISSN 2095-0241(Online)

CN 11-5984/TH

Postal Subscription Code 80-975

2018 Impact Factor: 0.989

Front Mech Eng    2011, Vol. 6 Issue (3) : 308-311    https://doi.org/10.1007/s11465-011-0233-z
RESEARCH ARTICLE
Experimental research on ductile fracture criterion in metal forming
Song YU(), Weiming FENG
Department of Engineering Mechanics, School of Civil Engineering, Shandong University, Ji’nan 250061, China
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Abstract

Ductile fracture criterion is key limitation parameter in material forming. Accuracy predicting surface and internal failure in plastic deformation process affects on the technology design of workpiece and die greatly. Tension, compression, torsion and shearing test on 45# steel are utilized for providing the experimental values of the critical values at fracture, and 11 widely used ductile fracture criterion are selected to simulate the physical experiments and their relative accuracy for predicting and quantifying fracture initiation sites are investigated. The comparing results show that metal forming process under high triaxiality can be estimated successively using both Normalized Cockcroft-latham and the Brozzo ductile fracture criteria, but the Ayada and general Rice-Tracey model work very well for the low triaxiality cases.

Keywords ductile fracture criteria      metal forming process      material experiment      stress triaxiality     
Corresponding Author(s): YU Song,Email:yusong@sdu.edu.cn   
Issue Date: 05 September 2011
 Cite this article:   
Song YU,Weiming FENG. Experimental research on ductile fracture criterion in metal forming[J]. Front Mech Eng, 2011, 6(3): 308-311.
 URL:  
https://academic.hep.com.cn/fme/EN/10.1007/s11465-011-0233-z
https://academic.hep.com.cn/fme/EN/Y2011/V6/I3/308
Plastic propertyTorsion testTensile test
σs(MPa)436410
σb(MPa)756710
Percentage elongation88%28%
Yield flow area≈0%6. 7%
Percentage reduction in cross-section area<2%52%
Tab.1  Material properties of 45 steel
Fig.1  True stress-strain curve for 45steel
Fig.2  Three tensile specimens. (a) Before fractured; (b) after fractured
Name of criterionTension-1Tension-2Tensile-3TorsionShearMMDDF
Normalized Cockcroft & Latham 0. 7450. 6060. 5630. 6020. 60. 623210%29%
Cockcroft & Latham580478413491489490. 211%34%
Mc Clintock1. 621. 531. 491. 071. 551. 45214%38%
Frudenthal51932725093374155446%123%
Rice & Tracy1. 421. 431. 490. 55671. 71. 3230%86%
Brozzo0. 7450. 6360. 5610. 60. 60. 62810%29%
Oyane1. 591. 471. 340. 4211. 431. 2534%93%
Ayada0. 330. 3450. 3340. 008810. 370. 27749% 121%
Osakada 0. 0820. 0750. 06130. 4498617. 33198%495%
Zhao & Kuhn0. 0310. 0405 0. 05120. 00050948597195%500%
Max (Eff. Stress/UTS)1. 61. 721. 860. 81. 811. 55825%64%
Stress triaxiality σm/σˉ0.33-1.00.76-0.810.97-1.00-0.1-0.9--0.5
Tab.2  Threshold values of the ductile fracture criterion in tests
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