PSI - Issue 68

T. Korschinsky et al. / Procedia Structural Integrity 68 (2025) 1196–1202 Korschinsky et al. / Structural Integrity Procedia 00 (2025) 000–000

1200

5

• The grey datapoints in the cyclic stress-strain curve of Figure 4 show a mismatch between the course of the experimental datapoints and the equations by Ramberg-Osgood (Ramberg, et al., 1943). The explanation for this behavior lies in the strain-amplitude dependent softening behavior that leads to a faster softening for higher strain amplitudes. Thus, the determined stress amplitude at 50 % of damage is lower at strain amplitudes >0.25 % than at the maximum of 0.25 %. Further information as well as further investigations on the anisotropic behavior are given in (Korschinsky, et al., 2024). • The plastic portion of the cyclic stress-strain curves of Figure 4 show a very flat slope. Consequently, a small change in stress leads to a severe change in strain. Thus, a very accurate calculation considering extensive influencing factors like the micro-supporting effect is mandatory.

Figure 4: Stress-strain curves of cross- and lengthways extracted specimens

Figure 5: Softening behavior of EN AW-1050A H24

3.2. Modelling of the cyclic transient material behavior using the Chaboche combined hardening model In Figure 6 (a,c,e) the hysteresis loops simulated using the Chaboche combined hardening model is shown for a strain amplitude of 0.6 %, 0.4 % and 0.2 % and . =−1 . Neither the shape of the hysteresis nor the reversal points are met satisfactorily. The reason for this is related to the equations (1) and (2). The exponential terms tend towards a certain