PSI - Issue 68

Rintaro Tsuda et al. / Procedia Structural Integrity 68 (2025) 674–680 R. Tsuda et al. / Structural Integrity Procedia 00 (2025) 000–000

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Fig. 3. Comparison of total, single-phase stress and total equivalent plastic strain relationship from experiment and FEM. (a) Total at 173K, (b) Total at 20K, (c) Matrix at 173K, (d) Inclusion at 173K, (e) Matrix at 20K and (f) Inclusion at 20K 6. Impact of this module on fracture toughness simulation Simulation of CTOD tests (ISO12135,2016, WES1108,2016, ASTM E1820,2018) using 25 mm thick three-point bend specimens was performed. By comparing the conventional method, which simply converts the tensile test results using smooth round bar specimens into equivalent stress-equivalent plastic strain relationship, with the present method, which takes into account the change in the constitutive equation due to SIMT, the problems of the conventional method are discussed. Fig. 4 shows the maximum principal stress near the crack tip. At the same CTOD level, the results of the developed method show larger values at the crack tip than those of the conventional method. This suggests that the conventional method may underestimate the stress value in the region where much transformation occurs, because the SIMT is not taken into account.

Fig. 4. Comparison of max principal stress near the crack tip