PSI - Issue 18

Matus Margetin et al. / Procedia Structural Integrity 18 (2019) 663–670 Matus Margetin at al / Structural Integrity Procedia 00 (2019) 000–000

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The calculated fatigue lifetime and critical plane orientation is summarized in Figure 5.

Fig. 5. Fatigue lifetime prediction and critical plane orientation: 1- Findley, 2- McDiarmid, 3- Matake, (a) S355; (b) C55.

The fatigue damage as a function of plane orientation for each loading cycle as well as total accumulated fatigue is shown on Figure 6 for both loading sequence. Red dots mark critical plane corresponding to criterion definition. For Findley criterion it is plane with maximal damage in case of each individual amplitude as well as in case of total loading segment. For McDiarmid and Matake criterion they are planes with maximal shear stress amplitudes for individual cycles, and planes of total maximal damage for whole loading cycle.

Fig. 6. Damage for each cycle as well as for whole segment as a function of plane orientation, (a) tension followed by torsion; (b) sequence composed from tension, torsion and their proportional combination.