PSI - Issue 37

Zijah Burzić et al. / Procedia Structural Integrity 37 (2022) 269 – 273 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

270

2

importance in order to better understand the behaviour of large-scale welded structures subjected to both static and dynamic (cyclic) loads, such as bridges, as it is shown in this paper.

2. Experimental investigation 2.1. Results of NDT testing

Few defects are shown in Fig. 1, as detected in welded joints by penetrants and fluorescent light (PT). It is clear that these crack-like defects need reparation to prevent failure. The lengths are given in mm, obviously presenting unacceptable cracks, especially since the whole construction is heavily loaded, including fatigue loading.

Fig. 1. Defects in Gazela welded joints, marked by fluorescent light

2.2. Fracture Mechanics testing Standard fracture mechanics testing was done, [13], using 3PB specimen, Fig. 2, to provide values for K Ic via J Ic , as shown in Table 1.

N

B +_ 5% 0,8 m 

A

A

60 ° nom

a

2,3 W

2,3 W

A // 0,2%W

0,8 m 

Detalj ” A ”

2,5%W A

a) Pravougli presjek

W+_ 2,5%

Fig. 2. Standard 2PB specimen used for testing

N

B +_ 5%

A

Table 1. Fracture mechanics parameters (min value of 3 specimens)

0,8 m 

A

Jic (kJ/m2)

K Ic MPa∙ √ m

a c (mm) 15.72 30.89 a

Specimen

60 ° nom

1 (TL) 2 (LT)

29.7 58.5

81.8

2,3 W

2,3 W

A // 0,2%W

0,8 m 

114.8

Detalj ” A ”

b) Kvadratni presjek

2,5%W A

W+_ 2,5%