Study On Structural Mechanics And Fatigue Performance Of LNG Cryogenic Hose

At present,liquefied natural gas(LNG)is produced through floating liquefied natural gas plants(FLNG).Usually,LNG cryogenic hoses are used to transport to LNG carriers for transportation,and LNG cryogenic hoses are also used to transport to storage units after arriving at the destination.In view of the long-term effect of LNG cryogenic hose under the action of ultra-low temperature medium and the fatigue load caused by the hull movement caused by wind and waves,it is very important to accurately grasp the influence of structural characteristics of LNG cryogenic hose on its mechanical and fatigue properties,and also the key to ensure the efficient and safe and stable delivery of LNG cryogenic hose.In this thesis,a three-dimensional finite element numerical model is established for the nonlinear structural characteristics of typical LNG cryogenic hoses.Based on the Ludwig flow stress model,a material property model considering the cold forming hardening effect of bellows is established,and its accuracy is verified by combining the experimental data of classical literature.Combined with the PYTHON secondary development technology of ABAQUS software,Graphical User Interface(GUI)for parametric modeling of LNG cryogenic hoses was compiled,which laid a foundation for subsequent rapid model parameter analysis.Then,the research models of LNG cryogenic hoses with different structural characteristics were established based on the parametric modeling program,and the mechanical responses of LNG cryogenic hoses under axisymmetric loads and bending loads were carried out.The sensitivity of the parameters related to the tensile armor layer and the bellows is analyzed,and the nonlinear slip and hysteresis mechanical properties of the hose are found and the sensitivity law is summarized.Finally,the fatigue analysis of the LNG cryogenic hose is carried out,and the fatigue sensitivity of different parameters of the LNG cryogenic hose is analyzed,and the fatigue life and the sensitivity law of each layer structure of the LNG cryogenic hose are summarized.The research results of this thesis can provide support for the selection,optimization design,fatigue analysis and verification of LNG cryogenic hoses in practical engineering.