PSI - Issue 38

Tobias Jonsson et al. / Procedia Structural Integrity 38 (2022) 411–417 Jonsson, Narström and Barsoum / Structural Integrity Procedia 00 (2021) 000 – 000

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In which B is the length of the weld, h is the height of the weld and θ is the angle relative the specimen the force is applied in theory should be 90°. By combining equation 1 and equation 2 two conditions can be derived which gives the maximum force that can be applied fulfilling the standard as

(3) Since β w ≤ 1 only the lower condition in equation 3 needs to be considered since it is a lower limit for the force F if θ ≈ 90° . The maximum load at failure is presented in Figure 5 together with the recommended maximum load according to Eurocode 3 where the condition was determined both with the ultimate tensile strength (UTS) from SSABs datasheet for Strenx® 1100Plus and from the mean of the UTS derive in the tensile tests.

Figure 5. Tensile strength of Strenx® 1100Plus butt welds.

4.3. Fatigue Strength In figure 6-8 the fatigue test data are presented for the Strenx® butt welds in as-welded condition, TIG dressed and HFMI treaded, respectively. The mean slope, the characteristic S-N curve and the corresponding FAT class according to IIWs recommendations is also presented. It can be observed that the characteristic curve for the HFMI treated specimens is 9 FAT classes higher than for as-welded, i.e. one FAT class higher as recommended in (Marquis and Barsoum, 2016). It is also observed that the characteristic curve for the TIG dressed specimens 7 FAT classes higher than for as-welded, i.e. one FAT class higher as recommended in (Yildirim, 2015). Since some of the specimens were not run to weld failure the result is conservative and perhaps even greater e ff ect of the treatment could have been observed.