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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To simulate the condition of an existing component at the end of the design working life the specimens were pre damaged to a damage sum of D = 1.0 by cyclic loading and subsequently checked for fatigue cracks by dye penetrant testing (PT). When crack-free, the post-weld treatments grinding or hammer peening were applied. The treated specimens were then tested until the failure criterion was reached, see Figure 3. The fatigue tests were carried out using a high-frequency resonance pulsator (SincoTec Power Swing 600) with a constant load ratio of R = 0.1. A frequency deviation of Δ f = -0.10 Hz was chosen as failure criterion, with a typical crack length of at least 40 mm (rail clamp, transverse stiffener) or 10 mm (lateral attachment).

Figure 3. Test sequence: a) pre-damaging, b) dye penetrant testing, c) treatment: grinding/HFMI, d) fatigue test

Two different grinding methods – disc and burr grinding - were investigated. Disc grinding is only applicable to structural details with good accessibility e.g. the rail clamp during the exchange of the rail and thus was only applied to that detail using a flap disc (P120), see Figure 4. Because of the poor accessibility through the web plate, disc grinding could not be performed on the weld seam of the transverse stiffener and therefore burr grinding was applied, see Figure 5.

Figure 4. rail clamp – a) as-welded, b) treated by disc grinding

Figure 5. transverse stiffener – a) poor accessibility through web plate, b) burr grinder used on the weld toe