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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Fig. 4. Fracture locus of AISI 1045 steel.

Figures 2, 3, and 4 suggest that mixed mode fracture appears to dominate in majority of experiments and combination of tensile mode and shear mode fracture loci (in one curve) can be more convenient than presenting each of these fracture loci separately. Therefore, the following hybrid model is proposed in order to combine tensile mode and shear mode fracture models. � � � � � � ��� � � � � ��� � � ��� � � � ��� � � � � �� � � � � � � ��� � ���� (5) The hybrid model requires two calibration parameters, and ���� . Here, determines the contribution of shear in the fracture mode. When equals to one ( ��� ), the fracture is pure shear mode fracture, whereas equals to zero ( ��� ) correspond to pure tensile mode fracture. A more detailed investigation of the hybrid model is a topic of The current investigation encompasses prediction of fracture loci of various metallic materials using two one parameter fracture criteria, i.e., the energy balance (KAEB) concept and the maximum shear stress (MSS) criterion. The criteria are implemented into two aluminum alloys and two structural steels to evaluate the capabilities of both criteria. KAEB concept is more versatile than the MSS criterion as it can capture the non-symmetry as well as both Lode angle and stress triaxiality dominated cases in the fracture locus. Moreover, as mixed mode fracture appears to dominate in majority of experiments, a hybrid model that combines tensile mode and shear mode fracture is proposed. The hybrid model requires two calibration parameters. In fact, use of more than one experiment is suggested in model calibration regardless of the number of parameters required for the calibration as the choice of experiments utilized in parameter calibration can have a considerable impact on the results (see e.g., Akçay, 2020). ongoing study. 4. Conclusions