Page 214 - Biaxial Multiaxial Fatigue and Fracture
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198 I: LAGODA ET AL.
sion the critical plane is inclined of d4 with respect to the specimen axis, like in cyclic tests,
and the calculated fatigue lives are satisfactory. Under combined tension with torsion we ob-
tained different critical planes and the fatigue life calculation results are very similar. All the
calculated fatigue lives are satisfactory. Let us notice that for combined variable amplitude ten-
sion with torsion the mean angle of the fracture plane (Table 1) is &p = 15.8", and the calcu-
lated angle of the critical plane, being also the fracture plane (Table 4), is c&~I= 18". Thus, the
error in the fracture plane determination is only 2.2".
100
10
10 100
Fig.7. Comparison of the calculated fatigue life with experimental data for uniaxial variable
amplitude tension-compression, torsion and proportional tension-compression with torsion
according to Serensen-Kogayev hypothesis for a = 0.81
