Li, Yang (China National Offshore Oil Corporation) | Xie, Bin (China National Offshore Oil Corporation) | Xie, Wenhui (China National Offshore Oil Corporation) | Ni, Kankan (China National Offshore Oil Corporation)
During the operation period of the semi-submersible drilling platform, the floating status of the deep-water drilling platform have a great relationship with many factors, such as the waves, wave height, period, direction and wave phase angles, these factors combined different kinds of the sea states to affect the movement of the platform. According to the engineering experience and specification, dangerous wave condition of semi-submersible platform usually includes: sway, pitch, heave, yaw, roll, and surge. In addition, the semi-submersible drilling platform is a very complex structure which each component part and the local structure may emerge the maximum stress under different wave conditions and different phase angles.
According to the calculation and experience, the local hot spot stress usually appears in the local connection structure and other important local components. Local crack occurred in these places will threat platform security if we do not take corresponding measures to strengthen these areas.
In this paper, we focus on studying strengthening method for a crack area of the semi-submersible column, Strengthening method discussed including changing the T type beam dimensions, increase the toggle plate reinforced structure, through strengthening the toggle plate. The global strength of platform suffering from the critical wave load is analyzed after the critical wave load is calculated for the platform, so the load boundary of model for column and brace connection typical joint are calculated. The local strength of typical joint are calculated based on the load boundary and wave load, the results showed that structural strength of the typical joint. Based on the finite element method and according to the ABS and CCS specifications, analysis of semi-submersible drilling platform subjected to static strength in local office column crack load and environmental loading conditions. Comparative analysis of structural strength results of strengthened were concluded. It provides a theoretical basis and strengthening method feasible for strengthening the Deep-water semi-submersible drilling platform column key nodes.
Li, Yang (China National Offshore Oil Company Research Institute) | Chen, Yongjun (DMAR Engineering Inc.) | Shi, Zhongmin (China National Offshore Oil Company Research Institute) | Xie, Wenhui (China National Offshore Oil Company Research Institute) | Ni, Kankan (China National Offshore Oil Company Research Institute)
This paper focused on global fatigue analysis for deep-water Tension- Leg Platform based on simplified spectral method. TLP serve as a production facility for the Field, the hull is a stiffened plate and shell structure consisting of internal longitudinal stiffeners, girders, web frames, bulkheads, and flats, and the structure of the hull and upper deck are very complicated.
The purpose of this analysis is to validate the TLP for fatigue and identify fatigue sensitive areas for further local analysis. These global fatigue results are also later used to extract results for other local fatigue analysis. The load case considered for the global stochastic fatigue analysis is the operating condition. The stochastic fatigue evaluation is based on the ABS guide (2003-2007) for fatigue assessment of offshore structures. The load for the analysis was based on the normal operating condition and the wave scatter diagram was obtained. The analysis was carried out using SESAM suite of programs using its sub-modeling technique i.e. using displacements derived from global spectral fatigue analysis onto the sub-model boundaries. The radiation/diffraction theory is used to calculate wave load acting on TLP. The 3D FEA model of the rig is made using shell element, beam element, and mass element. According to long-term wave distribution of South China Sea, stress response of the global structure is calculated. The results from the detailed FE-models are used to calculate the fatigue life using STOFAT. The fine FEA model of typical joint is made, the result of global FEA is taken as the load boundary condition, the hotspot stress transfer functions are calculated accounting for hydrodynamic load and gravity load. The objective of this study is making a suggestion of a new simplified fatigue analysis method .Based on the Miner’s rule, the fatigue life of the typical joint are calculated using a simplified fatigue assessment method, and the results are compared with the results of the spectral-based fatigue assessment method, the simplified fatigue assessment method is verified at last.
Jiang, Zhe (General Research Institute, China National Offshore Oil Corporation) | Xie, Bin (General Research Institute, China National Offshore Oil Corporation) | Xie, Wenhui (General Research Institute, China National Offshore Oil Corporation) | Wang, Junrong (General Research Institute, China National Offshore Oil Corporation)
Lu, Haining (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University) | Xiao, Longfei (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University) | Li, Xin (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University) | Xie, Wenhui (China National Offshore Oil Corp. Research Center)
Xie, Wenhui (Deepwater Engineering Key Lab,, China National Offshore Oil Corporation Research Center) | Xie, Bin (Deepwater Engineering Key Lab,, China National Offshore Oil Corporation Research Center)