PSI - Issue 42

Stefan Sieberer et al. / Procedia Structural Integrity 42 (2022) 72–79 S. Sieberer et al. / Structural Integrity Procedia 00 (2019) 000–0 0

75

4

Fig. 3. Test set-up with the specimen mounted in the test facility. The eye was fixed with a steel bolt through the eye, and the shaft was clamped in hydraulic jaws.

fixed the lug eye in position. The force and displacement at the cylinder are measured by a load cell and a displacement transducer, respectively. For surface strains on the specimens, a digital image correlation (DIC) system was set-up. The DIC evaluation allows to obtain the strains over the surface. To compare the specimen performance, the sti ff ness of the shaft can be calculated from the cylinder force F assuming uniaxial stress in the CCF-reinforced cross-section A CCF , shown as the hatched area in the cut view of Figure 2, divided by the major principal surface strain measured in the shaft area ε 1 , sh as

F A CCF ε 1 , sh

E sh =

(1)

The strain concentrations at the neck and the closest visible point on the eye are given by

ε 1 , eye ε 1 , sh

ε 1 , neck ε 1 , sh

K neck =

and K eye =

(2)

and serve as a measure of comparison between the specimens to assess whether similar strain states exist despite the di ff erence in layer height and fibre volume fraction. The evaluation of the strains in the neck and eye area are given in Figure 4 in the results section. Furthermore, the bearing sti ff ness of the parts can be estimated as load F per vertical displacement y eye at the eye

F y eye

(3)

C bear =