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Numerical simulation of rotating bending process for U‐tubes in heat exchangers
Author(s) -
KIM H.S.,
JIN T.E.,
CHANG Y.S.,
KIM Y.J.
Publication year - 2009
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.2009.01386.x
Subject(s) - residual stress , bending , materials science , heat exchanger , structural engineering , cracking , internal pressure , finite element method , stress intensity factor , limit load , stress (linguistics) , stress corrosion cracking , bend radius , mechanics , composite material , corrosion , fracture mechanics , mechanical engineering , engineering , linguistics , philosophy , physics
Heat exchangers comprise thousands of tubes having U‐shaped portions. Rotating bending method has been widely utilized to make U‐bends. Although this method shows an excellent performance, cracks have been frequently detected in the U‐bends due to residual stresses induced by bending. In this paper, the bending process is simulated based on elastic–plastic finite element analyses in order to investigate the magnitude and distribution of the residual stresses including the effects of operating pressure. Analyses results show that the residual stress increases as the radius of U‐bend decreases and that operating pressure has a detrimental effect in terms of stress corrosion cracking at the intrados of U‐bend. It is thought that these results can be utilized for the estimations of fracture mechanics parameters such as limit load, stress intensity factor and J‐integral, prevention of the cracking, and establishment of the optimum inspection strategy for the heat exchanger tubes.