Ductile
Fracture
·
The photographs show a 304 stainless steel bolt that failed in tension
by ductile failure. This was one of a series of bolts that failed in the
same manner in a system designed to harvest power from wave motion.
·
Using the diameter change and the thread spacing in the deformed and undeformed
regions indicates that the material failed at about 30% elongation, a number
in good agreement with the specifications of the alloy.
·
The SEM photograph of the thread near the failure region clearly shows
a pair of parallel helical cracks that run in the thread bottom, and which
have crack surfaces at about 450 to the tensile axis. |
