In this
paper, cyclic loading behavior of carbon steel pressurized piping elbows are
described. Effects of internal pressure and bending moment amplitude on the
ratcheting rate are investigated. The AF kinematic hardening model is used to
predict the plastic behavior of the elbows. Material parameters and
stress-strain data have been obtained from several stabilized cycles of
specimens that are subjected to symmetric strain cycles. The results
show that the maximum ratcheting strain occurred mainly in the hoop direction
at flanks. Hoop strain ratcheting was found at intrados for individual
specimen. Ratcheting strain rate increases with increase of the bending loading
level at the constant internal pressure. The results show that the initial rate
of ratcheting is large and then it decreases with the increasing cycles. The FE
model predicts the hoop strain ratcheting rate to be near that found experimentally
in all cases that M/Ml≤1..
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