海洋平臺(tái)管節(jié)點(diǎn)的結(jié)構(gòu)和疲勞壽命分析的研究.pdf

1、
　　This thesis to a large extent provides a broad overview of some of the key factors in the structural analysis and design of off-shore structures considered under environmental loads to the offshore platforms (speci

2、fically about Bohai Bay China). Steel offshore structures are widely used for oil production and processing from different offshore oil fields, steel tubular joints usually called as ‘Jacket’ or ‘Template’ platforms whic

3、h are widely used during my research work for analysing the crack propagation criteria caused by different circumstances. Topics covered range from water wave theories, structure-fluid interaction in waves to the predict

4、ion of extreme values of response from spectral modelling approaches are also included in this thesis.
　　The subsequent mathematical model of oceans; related to wind, currents and wave loads are the key factor in thi

5、s thesis, from those the simplified form of these loads combination can get for simulation ocean structures by using the finite element software and CFD’s Computational Fluid Dynamics software. Since most of the control

6、management nodes work below the surface of the water so by using above mentioned software we analyse the dynamic and static performance under ocean loads of the offshore platform model in Bohai Bay, then extract a specia

7、l K-joint to analysis its multi-axial stress and fatigue behaviour in order to find the most dangerous joint in the structure. Discussions show the distribution of stress and fatigue life of the pipe node under multi-axi

8、al loading in different forms. The analysis mainly focuses on the stress and fatigue life appropriate characteristics to the actual situation of multi-axial loading case of the K-joint welding location and mainly environ

9、mental effect on the platform. Finally, calculate the initial crack presence of the stress intensity factor in the material, and those findings can provide preliminary ground work for the multi-axial fatigue study of com

10、plex and simple model structures.
　　This paper also studies and summarizes the structure reliability theory with jacket platform as the research object;it is the first time to aim and finds the most dangerous season

11、effecting Bohai bay offshore platforms by considering seasonal environmental loads. Environmental design data is extracted according to its geographical conditions in the form of wave, wind and current forces. Furthermor

12、e by using the Finite element analysis method more complex geometric problems can be solved; which is based on the finite element method of stress analysis of the welded tubular joints, accuracy of the result depends on