Frequency Domain Fatigue Evaluation on SCR Girth-Weld Based on Structural Stress  

作　　者：ZHANG Long ZHAO Tian-feng 

机构地区：[1]College of Safety and Ocean Engineering,China University of Petroleum(Beijing),Beijing 102249,China

出　　处：《China Ocean Engineering》2024年第2期255-270,共16页中国海洋工程（英文版）

基　　金：financially supported by the Director Fund of National Energy Deepwater Oil and Gas Engineering Technology Research and Development Center(Grant No.KJQZ-2024-2103)。

摘　　要：The Steel Catenary Riser(SCR)is a vital component for transporting oil and gas from the seabed to the floating platform.The harsh environmental conditions and complex platform motion make the SCR’s girth-weld prone to fatigue failure.The structural stress fatigue theory and Master S-N curve method provide accurate predictions for the fatigue damage on the welded joints,which demonstrate significant potential and compatibility in multi-axial and random fatigue evaluation.Here,we propose a new frequency fatigue model subjected to welded joints of SCR under multiaxial stress,which fully integrates the mesh-insensitive structural stress and frequency domain random process and transforms the conventional welding fatigue technique of SCR into a spectrum analysis technique utilizing structural stress.Besides,a full-scale FE model of SCR with welds is established to obtain the modal structural stress of the girth weld and the frequency response function(FRF)of modal coordinate,and a biaxial fatigue evaluation about the girth weld of the SCR can be achieved by taking the effects of multi-load correlation and pipe-soil interaction into account.The research results indicate that the frequency-domain fatigue results are aligned with the time-domain results,meeting the fatigue evaluation requirements of the SCR.

关 键 词：SCR girth weld random vibration self(cross)power spectrum structural stress method biaxial fatigue damage 

分 类 号：TE952[石油与天然气工程—石油机械设备] TG441.7[金属学及工艺—焊接]