Page 468 - Biaxial Multiaxial Fatigue and Fracture

452 M. WEICK AND 1 AKTAA

The fractographic analyses of the rupture surface with a scanning electron microscope revealed
areas with distinct oscillation lines. The orientation of the oscillation lines in the different areas
varied. Hence a multiple redirection of the crack can be assumed. The varying width of the
oscillation lines corresponds well with the assumption of varying crack growth rates. Between
the areas with oscillation lines, regions with a noticeable brittle fracture proportion and no
oscillation lines could be observed. In cause of this unequal distribution of the striations it is
not clear how to determine the crack growth rate our of the striation wide. In a further step an

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Fig. 10. Fracture surface

Fig. 11. Fracture surface