A fuzzy logic based approach for deciding the corrective action to minimize vibration induced fatigue damage on offshore pipework

摘要

Vibration velocity measurement technique (VVMT) coupled with the vibration assessment criteria (VAC), employed to decide the level of fatigue damage on the piping system is afflicted by two main shortcomings. First being that the data measured by VVMT is not a direct indicator of the remnant fatigue life (RFL) of a piping system. The second is that the distinction between different regions of the VAC used to identify the level of fatigue damage on the piping system is too rigid. The paper thus proposes a fuzzy logic based approach to overcome the aforementioned shortcomings. An illustrative case study is presented within which the Mamdani procedure is used to establish the relationship between input variables (vibration velocity and RFL) and the output variable (fatigue failure vulnerability index (FFVI)). Thereby, value of FFVI decides both the level of fatigue damage and the corrective action necessary to minimize fatigue damage on offshore pipework.