Real-time Monitoring And Load Characteristic Research Of Large Pipe-laying Vessel Stinger

The ocean contains a large amount of oil and gas resources,which are transported through oil and gas pipelines.One of the main equipment of this process is the deepwater pipe-laying vessel.The main load-bearing components of the pipe-laying vessel when carrying out pipe-laying operations are the stingers at the stern or the ship’s side.The stinger is inevitably affected by the harsh wind and wave environment at sea when sailing and carrying out pipe-laying operations,resulting in complex load forms.Longterm,high-intensity operations can lead to failure and damage to the stinger.Therefore,it is necessary to establish a complete real-time dynamic monitoring and early warning system for the stinger to analyze the impact of the working load and the marine environmental load on the stinger.This paper takes HYSY201 pipe-laying vessel as the research object,which is a large-scale deep-water pipe-laying vessel,and its working water depth can reach 2000-meters ultra-deep water.In this paper,a complete monitoring system is designed for the four-section stinger.The position of the monitoring point is determined by static analysis,hydrodynamic analysis,and fatigue analysis.After that,the layout creates a complete monitoring network,which ensures that the wiring is organized and the data collection is not cumbersome.The monitoring system fully considers the structural form and the working environment,which ensures real-time monitoring of the stress on the dangerous points on the stinger in the process of navigation and pipe-laying operations.The fundamental purpose is to find a location bearing relatively greater force and strengthen or modify it to improve or replace the aging parts due to fatigue factors.In the process of pipe-laying,the pipe-laying vessel is often subjected to many loads.The structure of the stinger is affected by the hull movement of the pipe-laying vessel,the wave load and wind load,the tensile force of the steel cable and the pipe pressure generated by the self-weight of the pipe.There are structural failure forms such as integral structural instability deformation,partial bar yield failure,and main hinge node shedding.To explore the influence of the load on the stinger in each frequency segment,this paper takes the actual data of the sea trial for analysis and performs timedomain analysis and spectral analysis.Through time-domain analysis,it is concluded that the chord of the stinger is subjected to greater stress and is the main load-bearing component.Through spectral analysis,the effective frequency interval is obtained,and the peaks of the functional spectral density of each monitoring point are summarized to obtain a peak list,which is proposed as a factor affecting the stress of the stinger’s monitoring position.Through the filtering method,the frequency separation of the monitoring stress data is successfully realized and the obtained data is separated into three different frequency segments.The time-domain analysis and spectral analysis are respectively performed to obtain various parameters of different frequency segments’ data and determined the effect of loads within different frequency bands on the stingers.At the end of the paper,based on the measured data,the environmental load on the stinger is reverse engineered.The distribution law of the frequency-separated data is studied and the load characteristics of the frequency segments that the data belongs to are analyzed to verify that most of the load distribution in the sea trial process obeys normal distribution.