PSI - Issue 57

Matthias Winkler et al. / Procedia Structural Integrity 57 (2024) 510–517 Matthias Winkler / Structural Integrity Procedia 00 (2019) 000 – 000

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2.5. Additional investigations Additionally the weld seam geometry was measured using a laser scanner (Keyence LJ-V7080) in as-welded and grinded condition. To determine the fatigue-relevant geometry parameters r, Θ and h, see Figure 9, the data of the scan was evaluated using a MATLAB script also used in (Wendler et al., 2023). The geometry parameters were then used to numerically calculate (Ansys Mechanical 2021) the notch factor K t of the investigated structural details, see Table 4. Burr grinding (transverse stiffener) resulted in an average increase of the notch radius r by 2,96 mm (558 %) and led to a reduction of K t by 25%. Angle grinding (rail clamp) averagely reduced K t by just 17,3 % due to less material removal and thus a lower increase of r .

Figure 9. a) laser scan of the weld seam, geometry parameters – b) as-welded, c) grinded

Table 4. Geometry parameters (mean values) and calculated notch factors

detail

condition as welded grinded as welded grinded

r [mm]

a [mm]

ω [°] 132.6 123.9 120.5

Θ [°] 47.4 56.0 59.5

h [mm]

K t [-]

Reduction K t [%]

0.69 1.44 0.53 3.49

- - -

3.46 2.86 2.64 1.98

rail clamp transverse stiffener

3.49

17.3

5.36

25.0

0.60

3. Summary and outlook It could be within the research project “NE - Industrie” (Dürr and Winkler, 2024) shown that the post-weld treatments for new structures - grinding and hammer peening - can also be successfully applied on pre-damaged components under the condition that there are no visible cracks. The absence of cracks should be verified by PT or other suitable procedures. The treatment led depending on the process to an average increase of service life by a factor of 2 to 28. Disc grinding showed the lowest effect, has a moderate processing speed and cannot be applied to details with poor accessibility like transverse stiffeners. Burr grinding showed the greatest effect but has the lowest processing speed. HFMI led to an average extension of service life by a factor of 17.1 and has the highest processing speed. The reduction of the notch factor K t by grinding the weld toe was quantified. In the further course of the research project “NE - Industrie” (Dürr and Winkler, 2024) other methods to strengthen pre-damaged components with visible cracks like the low-notch application of steel cover plates will be investigated. Furthermore, the efficacy of HFMI applied to repair weld seams will be investigated. 4. Acknowledgements The research project “NE - Industrie” (Dürr and Winkler, 2024) is being funded within the framework of a program for the applied research and development at universities for applied sciences with funds from the Bavarian State Ministry for Science and Arts.