PSI - Issue 75

Carl-Fredrik Lind et al. / Procedia Structural Integrity 75 (2025) 519–529 Carl-Fredrik Lind et al./ Structural Integrity Procedia (2025)

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6. Results 6.1. Welded joints: Case study

To evaluate the performance of the automated Master S-N curve method, a series of validation studies were conducted. The method was applied to four typical weld geometries and compared against results from the effective notch stress method, which serves as a high-accuracy benchmark. The maximum principal stress results are depicted for both solid and shell element models in Fig. 6 and Fig. 7. In Tab. 1The estimated life for each welded joint under the different test loads P is calculated using both the automated P. Dong with coarse mesh (8mm) and the effective notch method for a 50 % probability of fatigue failure at 2 million cycles. The estimated fatigue life using the automated master S-N curve is denoted PD N , and the estimated life using the effective notch stress is ENS N .In the worst case (Case 3), the automated method predicted a lower life than the benchmark, further supporting its use as a conservative screening tool. These findings are consistent with previous validations of the Master S-N method (Dong et al., 2007; Yaghoubshahi et al., 2017).

ENS N ) and the automated Master S-N curve

Table 1.Estimated lifecycles for the different case studies calculated using effective notch stress (

PD N ).

method (

Case 1

Case 2

Case 3

Case 4

Life [Cycles]

1[ ] P N 

120[ ] P N 

800[ ] P N 

960[ ] P N 

6 10 6 10



ENS N PD N

6956618 6286277

1120 1098

31

5823 7800



12.6

.

Figure 6. Maximum principal stress distribution in solid element models.