ABSTRACT
In this study, the failure of local sharp-dented 6061-T6 aluminum alloy tubes with
different diameter-to-thickness ratios submitted to cyclic bending are investigated.
Different diameter-to-thickness ratios of 16.5, 31.0 and 60.0 were considered. The
dent depths of tubes were considered from very small to approximately 0.6 times the
tube's wall thickness. From the experimental ovalization-curvature relationship, it
exhibited an increasing and ratcheting manner when the number of cycles increased.
The larger dent depth led to more asymmetrical ovalization-curvature relationship
and the greater increase of the ovalization. Furthermore, for a certain diameter-tothickness
ratio, five unparallel straight lines corresponding to five different dent
depths were found for the controlled curvature-number of cycles required to produce
failure relationship on a log-log scale. Finally, a theoretical model was proposed for
simulating the aforementioned relationship. Through comparison with the
experimental data, the theoretical model can properly simulate the experimental
findings.