PSI - Issue 33

Fuzuli Ağrı Akçay et al. / Procedia Structural Integrity 33 (2021) 279 – 286 Author name / Structural Integrity Procedia 00 (2019) 000–000

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KAEB) for stress triaxiality dominated cases (i.e., tensile mode) is presented as well in the same figure as a red solid line. An additional experiment (Test #4) is utilized in the determination of tensile mode fracture locus. An additional calibration parameter is required in order to obtain tensile mode fracture locus as this requires a separate model as in the following (Karr & Akçay, 2016) � � � � � � (4) The tensile mode and shear mode fracture loci of Al6061-T6 alloy suggest that the majority of experiments result in mixed-mode fracture as the experimental data points are confined in between two fracture loci. Only KAEB criterion is considered in the determination of fracture loci of ASTM A572 Gr. 50 steel ( � � ��� MPa, ������ ) and AISI 1045 steel ( � � ��� MPa, ������ ) as KAEB criterion can capture non-symmetry in the fracture locus as well as both tensile and shear dominated fractures. Special cases, such as plane stress loading, axisymmetric loading or plane strain loading are required in order to determine a single fracture locus in two-dimensional (2D) space. Therefore, determination of three-dimensional (3D) fracture locus is required in complex loading cases as a single 2D fracture locus does not accurately represent complex loading cases. As an alternative to 3D space representation, on the other hand, fracture locus of different (special) loading conditions can be represented by a separate curve of each if the fracture locus is determined in 2D space. The latter approach is utilized (for illustration purposes) in determination of fracture locus of both ASTM A572 Gr. 50 steel and AISI 1045 steel. Fracture loci of ASTM A572 Gr. 50 steel and AISI 1045 steel are displayed in Figure 3 and Figure 4, respectively. The first experiments (Test #1) are utilized in determination of tensile mode fracture locus of both materials, whereas Test #4 and Test #12 are utilized in determination of shear mode fracture locus of ASTM A572 Gr. 50 steel and AISI 1045 steel, respectively, as these experiments are the closest ones to a pure shear stress state.

Fig. 3. Fracture locus of ASTM A572 Gr. 50 steel.