PSI - Issue 42

Tereza Juhászová et al. / Procedia Structural Integrity 42 (2022) 1090–1097 Author name / Structural Integrity Procedia 00 (2019) 000–000

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(b)

Fig. 2 Numerical model of specimen with boundary conditions (a) and comparison of numerical and analytical methods used to calculate SIF (b) for P =25kN.

As it will be described further in text, for purpose of measurement the crack mouth opening displacement (CMOD) of the specimen, thin plates are needed to be installed on the bottom edge. As the differences between crack tip opening displacement (CTOD) and CMOD can’t be neglected, numerical model needed to be modified, adding segments of the size of the plates. In the lowest part, the displacement was measured to determine the relation between SIF and CMOD, results of which could be seen in Fig. 3(a). This dependence was further used to calculate SIF using experimental measurement of CMOD. Same process took place to determine dependency of relative crack length, i.e., a/W ratio, on CMOD. This dependency is shown in Fig.3 (b).

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Fig. 3. CMOD for P =25kN versus (a) corresponding crack length and (b) values of SIP K I .

5. Fatigue testing Experimental testing of single-edge notched specimen was executed using, high-frequency pulsator by ZwickRoell, Vibrophore 250, which generates dynamic loading by oscillating system in full resonance, see Vibrophores (2021). Three-point bending specimens were pre-notched in the middle of span, with initial notch of depth of 0.5 mm. Stress