PSI - Issue 42

A. Sulamanidze et al. / Procedia Structural Integrity 42 (2022) 412–419 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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notch root in the SENT sample. Under in-phase loading, the maximum of local hoop stresses corresponds to the combination of σ nom = max and T = max at t=30 sec. Under out-of-phase deformation, the maximum stress values are reached at each characteristic point of the loading cycle, i.e. 0, 30 and 60 sec. Moreover, fo r time t=30 sec at σ nom = min and T = max, there are significant negative stresses comparable with their values at the beginning and end of the loading cycle. This circumstance should be taken into account when analyzing the effects of crack closure under TMF testing. 4.2. Strain distributions in cracked specimen. According to test program, corresponding multi-physics computations were performed on single edge notched cracked specimen, using in-phase and out-of-phase TMF cycling with temperature ranges of 400 – 650°C. Nominal stress in each loading cycle ranging from 80 to 8 MPa and from 200 to 20 MPa for IP and OOP TMF conditions, respectively. All testing employed a triangular R = 0.1 waveform (Fig. 7).

Fig. 7. Stress-temperature waveform for IP and OOP TMF loading conditions.

Fig. 8. (a, b) COD and (c, d) strains behavior for first five IP and OOP TMF cycles.

A comparison of numerical results with experimental data is shown in Fig. 8a for a stress-strain response of the SENT cracked specimen during a TMF test for IP conditions. It should be noted that the good agreement between the