Issue 33

Y. Hos et alii, Frattura ed Integrità Strutturale, 33 (2015) 42-55; DOI: 10.3221/IGF-ESIS.33.06

Crack opening displacement  in mm

Force F in kN

Figure 11 : Crack opening displacement as function of the applied load, specimen R-028, pure tension-compression with F max =45 kN and R F =-1, steel S235.

3.00E‐02

2.50E‐02

E 43.1k N m ax load

2.00E‐02

1.00E‐02 Fictitious axial strain  yy in m /m 1.50E‐02

F 19.8k N ram ping dow n

D 19.5N ram ping up

G -1.1k N ram ping dow n

C 3k N ram ping up

H B 1.2k N ram ping up -6.3k N ram ping dow n

5.00E

‐03

I -18.3k N ram ping dow n -18.3k N ram ping up J

K -42.8k N m in load

0.00E+00

‐2

‐1

0

1

2

3

4

5

Position of point in the crack surface, origin at crack tip, distance in m m

Figure 12 : specimen R-028, pure tension-compression with F max

=45 kN and R F

=-1, steel S235.

Torsion loading The specimen R-003 has been tested under pure torsion loading with max M



1 M R   . Four cracks grew as

530Nm

and

shown in Fig. 13. The crack growth curve is shown in Fig. 14. The cracks initiate at the locations with the highest stresses. Starting at the initiation site the short cracks grow into a field of uniaxial stresses and their crack fronts are loaded under mode I. The longer ones of the cracks keep growing under 45° to the specimen axis until finally the crack path turns to a direction perpendicular to the specimen axis. The shorter two cracks immediately bend towards a direction perpendicular to the specimen axis.

47