# Risk Identification of FPSO Oil and Gas Processing System Based on an Improved FMEA Approach
## 6 Conclusions  
FMEA (failure mode and effect analysis) is an important safety and reliability analysis tool that is widely used in a wide range of industries. Due to its difficulty in acquiring precise assessment information on failure modes, the defects in the traditional RPN (risk priority number) modes, and the difficulty in building a complete fuzzy rule base, we proposed a new FMEA using the FER (fuzzy evidence reasoning) approach and fuzzy TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution), which adopt the comprehensive weighting method.  
The potential application of the proposed approach is examined and illustrated in FPSO (floating production storage and offloading system) oil and gas processing systems. It is more in line with the engineering practice to assign different weights to O (occurrence), S (severity), and D (detectability) for considering the influence of O, S, and D on the risk when determining the risk of the failure mode. When determining the objective weight of O, S, and D of failure mode, the variable weight method and entropy weight method start from the horizontal and vertical directions of O, S, and D of failure mode, respectively. That is, the weight of variable weight is adjusted according to the rating of O, S, and D in the same failure mode. Entropy weight is to adjust the weight of O (S or D) of any failure mode according to the values of O (S or D) in all failure modes. It provides a new idea for determining the weight. Further, the variable weight method is the comprehensive effect of assigning more weight to the larger value in O, S, and D, and less weight to the smaller value; and then by increasing the variable weight coefficient \(\alpha\), the risk result of failure mode can be magnified to attract attention. In particular, the proposed approach uses a fuzzy confidence structure to represent the uncertainty, diversity, and absence of O, S, and D ratings and give different beliefs.  
The improved FMEA method in this paper can be used in situations where the data obtained is incomplete and inaccurate, and in those systems where it is difficult to obtain reliable data. In determining the risk of failure mode, different evaluation indicators (risk factors) are considered to have different importance; different risk factors are given different weights; and more risk factors can be added as needed, making the improved FMEA more practical and flexible.  
Conceptualization, L.S. and L.W.; Funding acquisition, L.S. and J.K.; methodology, L.S., Y.W. and H.W.; validation, L.S. and Y.W.; formal analysis, L.S. and H.W.; investigation, L.W., L.S. and J.K.; resources, L.W. and Y.W.; data curation, L.W., Y.W. and H.W.; writing--original draft preparation, L.W.; writing--review and editing, J.K., Y.W. and H.W.; funding acquisition, L.S. and J.K. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China, grant number 51779267 and the Fundamental Research Funds for the Central Universities, grant number 19 CX02025A.  
Data Availability StatementData is contained within the article.  
The authors declare no conflict of interest.