PSI - Issue 47

A. Califano et al. / Procedia Structural Integrity 47 (2023) 842–848 Author name / Structural Integrity Procedia 00 (2019) 000–000

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different combinations of the welding parameters led, in the original joints, to different welding penetration lengths and consequently, the strains measured by S2 (namely, the strains on surface that is opposite to the welding bead) are affected by this phenomenon.

Fig. 4. (a) Load/Strain curves for all the six specimens obtained through S1 . (b) Load/Strain curves for all the six specimens obtained through S2 . Moreover, looking at the load/displacement curves for the six specimens (Figure 5), this aspect is even more evident. Focusing on curves for specimens 1A1, 1B1 and 1C1 (obtained with the same laser focus and laser power, but different laser speed), it can be noticed that the higher the laser speed, the lower the maximum load to failure. A similar trend can be found in the load/displacement curves for specimens 1D1, 1E1 and 1F1. In addition, as different welding penetration lengths are related to different welding widths, pictures of the fracture surfaces of the six specimens are reported in Figure 6. By a quick visual inspection, focusing, for example, on specimens 1D1, 1E1 and 1F1 (Figs 6d-6f), it can be qualitatively assessed that the higher the laser speed, the thinner the fracture surfaces and, therefore, the weaker the specimen.

Fig. 5. Load/Displacement curves for all the six specimens, together with their maximum loads to failure.