PSI - Issue 75

Elena Sidorov et al. / Procedia Structural Integrity 75 (2025) 276–288 Elena Sidorov et al. / Structural Integrity Procedia (2025)

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Tab. 1. Measured dimensions of the small-scale test specimens [mm]

Type

No. 205 209 305 309 605 609 408 413 508 513

b r

h r

t

t f

b sup

d

a 1,t

a 2,t

a 1

a 2

1 – Fig. 5a

50,10 50,12 50,41 50,50 49,60 49,73 50,35 50,22 50,22 50,29 50,60 50,44 50,37

29,50 29,38 28,91 28,94 28,88 29,04 50,00 49,06 49,45 49,86 29,42 29,46 29,57

19,41 20,15 20,29 20,01 20,05 19,74 19,92 20,26 19,86 19,32 15,02 15,01 14,95

13,30 13,40 13,54 13,74 13,60 13,61 14,00 14,24 13,70 13,30

30,34 30,45 29,50 29,64 30,02 30,23 32,24 30,26 29,91 31,14 99,39 99,70 99,65

18,60 18,84 17,28 17,83 19,10 17,83 18,86 20,18 19,60 19,00 20,60 20,80 20,65

7,66 6,75 7,28 6,42 8,69 7,84

8,14 7,49 7,07 6,16 7,50 7,13 7,25

6,34 6,56 6,68 5,65 7,28 7,37

6,53 6,29 6,39 5,46 7,04 6,68 6,34

2 – Fig. 5b

−

−

6,97

−

6,67

−

−

7,41

−

6,32

6,75 5,26 4,93 5,47

−

5,64 5,77 5,18 5,22

−

3 – Fig. 5c

10 15 19

− − −

5,86 4,79 4,86

5,21 5,08 4,73

3.4. Strain measurements During the tests, the vertical strains were recorded by conventional strain gauges at the front side of the test specimens. Five uniaxial strain gauges with a grid length of 3 mm were located one third of the flange thickness below the flange top surface with a spacing of 12,5 mm as shown in Figure 5. Full-field and point-based strain measurements were simultaneously performed with the high-resolution optical 3D measuring system ARAMIS 12M (stereo camera sensor) at the back side of the test specimens. Table 2 summarizes the parameters of the applied Digital Image Correlation (DIC) hardware. The data of the optical 3D measurement was analysed with the software ZEISS CORRELATE (2025) that uses DIC and point tracking algorithms to derive the full-field strain maps. For comparison reasons, the strains at the spots are of particular interest that correspond with the strain-gauge locations at the front side. To obtain these strains, the surface of the back side is aligned with the global coordinate system of the software. The visible small dot markings within the random speckle pattern, see Figure 6a to Figure 6c, facilitate to find these spots by means of vertical and horizontal auxiliary lines. Table 3 summarizes the parameters of the DIC analysis software.

Tab. 2. DIC hardware parameters

Camera

ARAMIS Adjustable 12M

Image resolution

4096 × 3000 pixels

Lens

Schneider Objective 35mm

Aperture

12

Field-of-View Image scale Stereo-angle

400 mm × 300 mm

unscaled

25°

Stand-off distance

400 mm

Image acquisition rate Patterning Technique

1 Hz

Base coat of white spray with black speckles