Page 269 - Biaxial Multiaxial Fatigue and Fracture
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The Multiaxial Fatigue Strength of Specimens Containing Small Defects 253
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200 pm
(a) Combined loading; ua = Za = 70 MPa
Axial direction
(b) Pure torsion; rW = 1 15 MPa
Fig. 8. Small non-propagating cracks emanating from hole at fatigue limit of
high strength brass; d = 500 pm.
propagating cracks is approximately normal to the principal stress, q, regardless of the
combined stress ratio, do. At a stress level just above the fatigue limit, the failure of the hole-
containing specimens resulted from the continuous propagation of a crack emanating from the
hole. These observations with Cr-Mo steel and brass further indicate that, as in the case of
