A New Micromechanical Criterion for Ductile Fracture of G20Mn5QT Cast Steels Under Shear Stress
- Resource Type
- Article
- Authors
- Yue Yin; Mengfei Li; Qinghua Han; Yan Lu; Jinghan Bai
- Source
- International Journal of STEEL STRUCTURES, 22(5), pp.1306-1321 Oct, 2022
- Subject
- 토목공학
- Language
- English
- ISSN
- 2093-6311
1598-2351
A new micromechanical criterion was proposed for ductile fracture caused by shear in low stress triaxiality regions. The infl uences of both the stress triaxiality and the Lode parameter were reasonably considered. The formula of the critical plastic strain for ductile fracture by shear was deduced based on the idea that the evolution of microvoids in materials under shear stresses is a successive procedure of nucleation, growth, elongation and collapse. Six shear specimens of G20Mn5QT cast steels were tested under monotonic tension. Three confi gurations of these specimens provided diff erent combinations of the stress triaxiality and the Lode parameter. The critical void compression ratio for the void collapse was determined based on unit cell analysis and the shape of the dimples on the fracture surfaces of the test specimens. Parameters in the proposed criterion were then calibrated for G20Mn5QT cast steels based on tests and complementary fi nite element analysis of the shear specimens. Finally, diff erent fracture mechanisms of G20Mn5QT cast steels were discussed.