TITLE:
The Ratcheting Behaviour of Stainless Steel Pressurized Piping Elbows Subjected to Dynamic Out-of-Plane Moments
AUTHORS:
S. J. Zakavi, M. Nourbakhsh
KEYWORDS:
Stainless steel, Piping Elbows, Ratcheting, Kinematic Hardening Model, Out-of-Plane Moment
JOURNAL NAME:
Modern Mechanical Engineering,
Vol.4 No.3,
August
15,
2014
ABSTRACT:
In this paper the ratcheting
behavior of four pairs of stainless steel elbows is studied under conditions of
steady internal pressure and dynamic conditions that induced out-of-plane external
moments at frequencies typical of seismic excitations. The finite element
analysis with the nonlinear kinematic hardening model has been used to evaluate
ratcheting behavior of the piping elbows under mentioned loading condition.
Material parameters have been obtained from several stabilized cycles of
specimens that are subjected to symmetric strain cycles. The direction of
maximum strain is at about 45° between the hoop and axial
directions. The results show that the direction of highest ratcheting is along
the hoop direction rather than the direction of maximum principal strain. Also, the initial rate of ratcheting is large and then
it decreases with the increasing cycles. Also, the FE method gives over
estimated values compared with the experimental data.