PSI - Issue 18

Rainer Wagener et al. / Procedia Structural Integrity 18 (2019) 490–500 Author name / Structural Integrity Procedia 00 (2019) 000–000

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(3)

Another advantage of the so-called Fatigue Life Curve is that, in the case of a fatigue approach, the course of the strain-life curve could be modified in order to estimate the damage impact of small amplitudes. Therefore, the well known Miner-modifications, such as elementary and Haibach could be adapted, Figure 4.

Figure 3: Three types of stress-strain behaviour, which occur within cyclic tests with constant amplitudes with aluminium wrought alloys of the 5xxx and 6xxx series

Figure 4: Fatigue Life Curve with adapted Miner-modification

3.1. Comparison of the different strain-life curves and derived stress-strain curves In Figure 5, a comparison of the conventional strain-life curve according to Coffin-Manson-Morrow-Basquin and the Fatigue Life Curve, as well as the resulting stress-strain curves derived by the compatibility conditions, are depicted.