Mathematical equation of unified fracture criterion

• Published in: Journal of materials science & technology 2024-09, Vol.192, p.1-5
• Main Authors: Li, X.T., Qu, R.T., Liu, R., Zhang, Z.J., Zhang, Z.F.
• Format: Article
• Language: English
• Subjects: Metallic glasses; Molecular dynamics simulation; Theoretical derivation; Three-axis loading; Unified fracture criterion
• ISSN: 1005-0302; 1941-1162
• DOI: 10.1016/j.jmst.2024.01.016

•The polynomial equations of unified fracture criteria are uniquely determined based on theoretical derivations.•The data of shear instability of metallic glasses under various stress states is obtained by atomistic simulations.•The ellipse criterion is the optimal choice within the polynomial range for the unified fracture criterion. Starting from the general form of polynomial unified fracture criteria, and then considering the fundamental principles of material fracture, we theoretically derived the unique equation forms for the first threeorder fracture criteria. Employing molecular dynamics (MD) simulations on the two typical metallic glasses, Cu65Zr35 and Ni62Nb38, under three-axis loading, the critical normal and shear stresses on the shear band plane were obtained at the point of shear instability. A comparative analysis between the derived fracture criteria and MD simulation results revealed that the two-order (2-O) fracture criterion exhibits the best agreement with the shear instability of metallic glasses. Furthermore, the validity of the 2-O fracture criterion at compressive stress state was also examined. Through theoretical derivation and MD simulations, this work concludes that the 2-O fracture criterion is the optimal choice within the polynomial range for the unified fracture criterion. [Display omitted]