Tension-torsion fracture experiments - Part II: Simulations with the extended Gurson model and a ductile fracture criterion based on plastic strain

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:50

Article

Xue, Zhenyu¹  Faleskog, Jonas²  Hutchinson, John W.³ 

[1] Jet Res Ctr, Halliburton Energy Serv, Alvarado, TX 76009 USA

[2] Royal Inst Technol, Dept Solid Mech, SE-10044 Stockholm, Sweden

[3] Harvard Univ, Sch Engn & Appl Sci, Cambridge, MA 02138 USA

关键词: Ductile fracture;    Fracture in shear;    Tension-torsion test;    Fracture criterion;    Lode parameter;   

DOI  :  10.1016/j.ijsolstr.2013.08.028

来源: Elsevier

【 摘 要 】

An extension of the Gurson model that incorporates damage development in shear is used to simulate the tension-torsion test fracture data presented in Faleskog and Barsoum (2013) (Part I) for two steels, Weldox 420 and 960. Two parameters characterize damage in the constitutive model: the effective void volume fraction and a shear damage coefficient. For each of the steels, the initial effective void volume fraction is calibrated against data for fracture of notched round tensile bars and the shear damage coefficient is calibrated against fracture in shear. The calibrated constitutive model reproduces the full range of data in the tension-torsion tests thereby providing a convincing demonstration of the effectiveness of the extended Gurson model. The model reinforces the experiments by highlighting that for ductile alloys the effective plastic strain at fracture cannot be based solely on stress triaxiality. For nominally isotropic alloys, a ductile fracture criterion is proposed for engineering purposes that depends on stress triaxiality and a second stress invariant that discriminates between axisymmetric stressing and shear dominated stressing. (C) 2013 Elsevier Ltd. All rights reserved.

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