Page 252 - Biaxial Multiaxial Fatigue and Fracture

236 C. GAIER AND H. DANNBAUER

This curve can be seen in Fig. 4. The additional term has been chosen in this way by adjusting
the second derivative of (20) to zero at 8 = 0". The corresponding safety factors are shown in
Fig. 18. The minimum has moved to 8= 0", which means, that with Eq. (20) the normal stress
will be critical for fatigue failure. The new results for the S/N-curves can be found in Fig. 19.

Fig. 16: Mohr's circle

. . . . . . . . . . . . . . . . . . . . Faligue Limil - - - - - .Slress Amplitude -Safely Factor

0 10 20 30 40 50 60 TO BO 90
Polar Angle [dag]
Fig. 17: Safety factor against fatigue limit in dependence on the polar angle 8