PSI - Issue 42

Miloslav Kepka jr. et al. / Procedia Structural Integrity 42 (2022) 762–768 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 4. Test stend and some of the tested samples.

Fig. 5. Measuring of hot spot structural stresses.

Since samples were tested by bending and the hot spot structural stress method was used to determine the stress in the test sample. The criterion for completing the test was an increase of the deflection of the test specimen (increase of the displacement of the loading cylinder). At such a moment, a macroscopic fatigue crack was already present on the tested specimen. Also, the change of cyclic stresses monitored during the test by means of installed train gauges made it possible to determine the beginning of the macroscopic crack propagation in the critical cross section of the tested specimen. Fatigue cracks formed and propagated as expected at the fillet weld edge.