PSI - Issue 13

Author name / Structural Integrity Procedia 00 (2018) 000–000

3

Daisuke Sasaki et al. / Procedia Structural Integrity 13 (2018) 1006–1009

1008

Fig. 2. Cross sectional diagram. (a) Definition ofthe minimum plate thick ness ∆ t and the interlock ∆ x . (b) Without hydrogen charging. (c) 19.6 x 10 − 4 A / m 2 charging.

Fig. 1. Load-displacement diagram.

Fig. 4. Microscopic fracture surface of the specimen with 19.6 A / m 2 charging. (b), (c) and (d) are corresponding to parts outlined by white dot lines in Figs.4(a), (b) and (c), respectively.

Fig. 3. Fracture surface of the specimen with 19.6 A / m 2 charging. (a) Overview of fracture surface. White arrows indicate steps on the fracture surface. (b) and (c) Side views of specimen after a clinching test. (b) Up per sheet. (c) Lower sheet.

10 − 4 A / m 2 charging had a uniform fracture surface thickness. On the fracture surface, there are many steps. It suggests that some cracks occurred and connected with each other, resulting in fracture. Figures 3(b) and (c) show side observation results using OM. Figures 3(b)and (c) are the upper and lower sheets, respectively. As shown in Fig.3 (b), the upper SPCC270 sheet with 19.6 A / m 2 charging fractured uniformly. The uniformly fracture indicates that cracks occurred at small plastic deformation.