Fretting cracking behavior of nub of last-stage blade for steam turbine

Nub-and-sleeve of last-stage blade for steam turbine is a part-span damper. The nub is vulnerable to fretting cracking since it is in contact with the sleeve under centrifugal force, and a small-amplitude oscillatory movement occurs at the nub-sleeve contact interface due to the blade vibration duri...

Full description

Saved in:
Bibliographic Details
Published in:Journal of mechanical science and technology 2020-04, Vol.34 (4), p.1523-1529
Main Authors: Kim, Kihyeon, Cho, Sung-San, Hwang, Dong Hyeon
Format: Article
Language:English
Subjects:
Amplitudes
Centrifugal force
Contact force
Control
Dynamical Systems
Engineering
Fretting
Industrial and Production Engineering
Industrial research
Lithium
Mechanical Engineering
Original Article
Slip
Steam turbines
Vibration
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Nub-and-sleeve of last-stage blade for steam turbine is a part-span damper. The nub is vulnerable to fretting cracking since it is in contact with the sleeve under centrifugal force, and a small-amplitude oscillatory movement occurs at the nub-sleeve contact interface due to the blade vibration during operation of turbine. The present study developed a rig test that mimics fretting behavior at the nub-sleeve contact interface and reproduces fretting cracking of the nub. The rig tests reveal that fretting cracking occurs if the contact interface is in partial slip state and the tangential contact force amplitude is sufficiently large. The minimum tangential contact force amplitude for cracking increases with the normal contact force. Moreover, under the partial slip condition, the tangential contact force amplitude increases with the imposed displacement amplitude and its maximum value increases with the normal contact force.
ISSN:1738-494X
1976-3824
DOI:10.1007/s12206-020-0314-1