Page 171 - Biaxial Multiaxial Fatigue and Fracture

156 J LIU AND H. ZENNER

1.4
1.3 - -
SIH
1.2 0 34Cr4 [28]
1.1 - 42CrM04[30] c
-
n
1 El
0
0.9
0.8 0 25CrMo4[31]
0.7 0 steels [32]
0.6
0" 30" 60" 90"
phaseshift tiw

Fig. 7. Effect of a phase shift between a cyclic normal stress and a cyclic shear stress

1.4
1.3
0 42 CrMo4 [l 11
1.2
1.1 -
1 '1
0.9
0.8
0.7

0" 30" 60" 90" 120" 150" 180"
phaseshift 6,,

Fig. 8. Effect of a phase shift between two cyclic normal stresses

For two cyclic normal stresses, only test results with pulsating loads are available, because
of experimental difficulties. The effect of a phase shift 4 between two pulsating normal
stresses is small within the range from 0" to W", and results in a significant decrease in the
fatigue limit within the range from 90" to 180°, Fig. 8. A slight increase in strength is observed
in the vicinity of 60". A phase shift 4 =180" between two normal stresses of equal magnitude