Page 32 - Biaxial Multiaxial Fatigue and Fracture

Assessment of Welded Structures by a Structural Multiaxial Fatigue Approach 17

350 0 Bending, R=- 1
Torsion, R=-1
0 In phase bending and torsion, R=- 1
250 A Out of phase bending and torsion, R=- 1
h
k
E
P
150

50
1 E+04 1 E+05 1 E+06 1 E+07
Number of cycles to failure N

Fig. 12. Results of Sonsino’s through crack fatigue tests compared with the design curve TO-N

Another way to illustrate the results is using the Dang Van’s diagram (Fig. 13.). The
2oorr
remarkable result is that the proposed method is predictive and very robust since various
thicknesses, various geometries of welded structures as well as various loading paths are
experienced with success.

Sonsino, Mz R=- 1
0 Sonsino, Fx, R=- 1
0 Sonsmo, Fx&Mz (In phase), R=- 1
A Sonsino, Fx&Mz (Out of phase), R=- I
150
-c- fatigue criterion at 1 million cycles

50 -

,

0 100 200
P (MPa)
Fig. 13. Mean values of Sonsino’s through crack fatigue test results at lo6 cycles presented in
the Dang Van’s diagram and compared to the fatigue criterion at 1 million cycles.