TY - JOUR
T1 - A unified fracture criterion considering stress state dependent transition of failure mechanisms in bcc steels at -196 °c
AU - Shen, Fuhui
AU - Münstermann, Sebastian
AU - Lian, Junhe
N1 - Funding Information:
thyssenkrupp Steel Europe AG is gratefully acknowledged for materials supply and financial support. Simulations were performed with computing resources granted by RWTH Aachen University under project rwth0241.
Publisher Copyright:
© 2022 The Author(s).
PY - 2022/9
Y1 - 2022/9
N2 - The fracture properties of a high-strength steel with a body-centered cubic (bcc) crystal structure have been characterized at -196 °C by performing tensile tests with different specimen geometries, three-point bending tests using Charpy specimens, and fracture mechanics tests, covering a broad range of stress states under quasi-static conditions. Both strength and ductility of the bcc steel are significantly increased when the temperature is decreased from room temperature to -196 °C. Enormous plasticity occurs in the material during tensile tests using various specimens at -196 °C, while macroscopic brittle fracture takes place in high triaxiality scenarios. A stress state dependence of ductile to brittle transition properties is observed, as the failure mechanisms at -196 °C change from cleavage fracture to shear failure with decreasing stress triaxiality. A unified stress-state-dependent fracture criterion, which considers the transition of failure mechanisms, is proposed to describe the fracture properties of similar bcc materials at cryogenic temperatures. The threshold triaxiality at which the transition of failure mechanisms takes place is a material property that is determined by the strain hardening capacity and fracture strength. In addition, a probabilistic formulation relying on the extreme value distribution has been incorporated into the model to render the statistical nature of cleavage fracture.
AB - The fracture properties of a high-strength steel with a body-centered cubic (bcc) crystal structure have been characterized at -196 °C by performing tensile tests with different specimen geometries, three-point bending tests using Charpy specimens, and fracture mechanics tests, covering a broad range of stress states under quasi-static conditions. Both strength and ductility of the bcc steel are significantly increased when the temperature is decreased from room temperature to -196 °C. Enormous plasticity occurs in the material during tensile tests using various specimens at -196 °C, while macroscopic brittle fracture takes place in high triaxiality scenarios. A stress state dependence of ductile to brittle transition properties is observed, as the failure mechanisms at -196 °C change from cleavage fracture to shear failure with decreasing stress triaxiality. A unified stress-state-dependent fracture criterion, which considers the transition of failure mechanisms, is proposed to describe the fracture properties of similar bcc materials at cryogenic temperatures. The threshold triaxiality at which the transition of failure mechanisms takes place is a material property that is determined by the strain hardening capacity and fracture strength. In addition, a probabilistic formulation relying on the extreme value distribution has been incorporated into the model to render the statistical nature of cleavage fracture.
KW - Cleavage fracture
KW - Fracture criterion
KW - Shear fracture
KW - Stress states
KW - Threshold triaxiality
UR - http://www.scopus.com/inward/record.url?scp=85134890388&partnerID=8YFLogxK
U2 - 10.1016/j.ijplas.2022.103365
DO - 10.1016/j.ijplas.2022.103365
M3 - Article
AN - SCOPUS:85134890388
SN - 0749-6419
VL - 156
JO - International Journal of Plasticity
JF - International Journal of Plasticity
M1 - 103365
ER -