PSI - Issue 54

Naveen Kumar Kanna et al. / Procedia Structural Integrity 54 (2024) 196–203 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Fig. 2. Specimen geometry

2.1. Laser notch preparation In order to get a defined crack initiation site, a laser notch has been introduced into the specimen at the center as depicted in Fig. 3a. A laser engraving system (TruMark Station 5000 (Fig. 3b)) was used to produce notches with a length of 2 mm with the laser parameters listed in Table 1. These laser parameters are material and heat treatment specific. The depth of the laser notch can be produced by varying the number of repetitions of the laser. Additionally, cross-like symbols were engraved on the specimen at a distance of 1 mm from the notch root on either side for spot welding the 3 potential probes on the specimen at the desired position as depicted in Fig. 3a.

a

b

Notch

Spots for potential probes

Fig. 3. (a) Laser notch and the 3 potential probe positions on the specimen; (b) TruMark Station 5000 laser engraving system.

Table 1. Calibrated laser parameters. Parameter

Quantity

Laser power [%] Velocity [mm/s]

25 20

Track width [mm] Pulse frequency [Hz] No. of repetitions

0.05 2000 50

By adopting appropriate laser parameters, the resultant notch root is smooth without any keyholes as shown in Fig. 4.