Reliability analysis of subsea Christmas tree structure based on fuzzy fault tree

In order to evaluate the reliability of subsea Christmas tree structure, a reliability analysis method based on fuzzy fault tree is proposed in this paper. First of all, by analyzing the configuration of the subsea Christmas tree from different manufacturers, the typical structure of the subsea Christmas tree is determined, and the failure tree model of the subsea Christmas tree structure is established based on the external load analysis. Then, the fuzzy comprehensive evaluation method is used to obtain the failure rate of the bottom event of the fault tree. The reliability indexes such as the failure rate of the top event, the reliability and the reliability life curve are calculated by quantitative analysis. Finally, the importance of the fault tree is analyzed. The results show that the key importance of "tree body inner wear" is the highest and has the greatest impact on the top event. It is a weak link in the structure and should be paid attention to. The research results can provide technical reference for the risk assessment of the subsea Christmas tree, and provide certain guiding significance for the design and manufacture of the subsea Christmas tree.