PSI - Issue 75

Felix-Christian Reissner et al. / Procedia Structural Integrity 75 (2025) 382–391 Felix-Christian Reissner / Structural Integrity Procedia 00 (2025) 000–000

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Fig. 2. E ff ect of magnitude of the standard deviation on parameter estimation accuracy.

5.3. Runout Ratio

The final investigation examines the e ff ect of the runout ratio on model performance, as shown in Fig. 3. The ratio of runouts is varied between 0 % and 20 % runouts relative to the total number of S-N data pairs. The evaluation in fatigue-life direction is highly biased across the full range of runout ratios. The evaluation in load direction delivers accurate results for low runout ratios up to 5 %. At higher runout ratios, the load amplitude S a , k is increasingly overestimated. In addition, it tends to overestimate the slope k 1 . The piecewise evaluation performs better as the runout ratio increases. In particular, for runout ratios above 10 %, it begins to outperform the evaluation in the loading direction. The pointwise evaluation shows a similar result as the piecewise evaluation. However, it is slightly better in estimating the slope k 1 . In summary, the evaluation in load direction performs best at low runout ratios. As the runout ratio increases, the pointwise and piecewise evaluation become the most accurate.

Fig. 3. E ff ect of the runout ratio on parameter estimation accuracy.