YANG Jiandong,GAO Hongbo,XU Yangyang,et al. Study on random vibration fatigue evaluation method of small branch pipe welded joints in nuclear power plants[J]. Journal of Mechanical Strength,2026,48(6):110-116.
YANG Jiandong,GAO Hongbo,XU Yangyang,et al. Study on random vibration fatigue evaluation method of small branch pipe welded joints in nuclear power plants[J]. Journal of Mechanical Strength,2026,48(6):110-116.DOI: 10.16579/j.issn.1001.9669.2026.06.012.
Study on random vibration fatigue evaluation method of small branch pipe welded joints in nuclear power plants
Aiming at the fatigue life evaluation of welded joints of small-bore pipes in nuclear power plants under random vibration loads
fatigue life evaluation methods based on test data
the in-service fitness-for-service (FFS) assessment method specified in ASME FFS-1 and the equivalent structural stress method were investigated.
Methods
2
The fatigue life evaluation approaches based on test data
ASME FFS-1 fatigue analysis method and equivalent structural stress method were compared
and comparative verification was conducted via random vibration fatigue tests.
Results
2
The research results reveal that the ASME FFS-1 fatigue analysis method is susceptible to mesh sensitivity when dealing with complex structures
which may lead to excessively conservative fatigue life evaluation results. The fatigue analysis method based on measured stress also presents high conservatism and may cause unnecessary increase in maintenance costs. In contrast
the equivalent structural stress method can more accurately take into account the local stress concentration effect of welded joints
effectively adapt to complex random vibration environments
and possesses higher prediction accuracy and engineering applicability in fatigue life prediction. It can provide an important reference for formulating effective preventive maintenance strategies.
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