PSI - Issue 19

Jennifer Hrabowski et al. / Procedia Structural Integrity 19 (2019) 259–266 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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welded condition, too. If the thickness of the transverse stiffener is greater than the thickness of the base plate, also FAT 71 is valid.

8mm

4mm

8mm

60mm

Fig. 3. Plate with transverse attachments on both sides

The imperfections of the welded transverse stiffeners can be seen in the side view of the specimens on the right side in Figure 3. On the one hand, there is a small gap between the stiffener and the base plate on some specimens. On the other hand, an offset of the upper and lower transverse stiffener may occur. In addition, an angular misalignment of the base plate is observed. The gaps between the stiffener and the base plate and the offset of the stiffeners have negligible influence on the fatigue resistance. But the limit value for the permissible angular misalignment of  ≤ 2 ° according to ISO 5817 (2006) is exceeded for many samples. Therefore, an evaluation including the additional bending stresses is also carried out for samples with welded transverse stiffeners. In the FAT class of Table 3.1 (Hobbacher 2016) for non load-carrying, transverse stiffeners, a factor of which is already considered of k m = 1.2 is indicated. This corresponds to an angular misalignment  = 1.0°. Therefore, in Figure 4, the stress ranges  are corrected only for samples with an angular misalignment  > 1 ° and a common evaluation of all steels is made.

Fig. 4. Evaluation for very high-strength steel plates with transverse attachments considering the corrected stress range for samples with angular misalignment  > 1.0°