Research And Application Of Dynamic Monitoring And Early Warning System For The Structure Of Stinger In Operation

Deepwater pipelay vessel is the main equipment of laying oil and gas submarine pipelines,and its structure safety can not be neglected.As the assistant equipment of vessel,the stinger is endured complicated loads under long-term wind and sea environment and the failure features are mainly transient high stress and long-term fatigue damage.At present,the inspection for stinger structure is still based on manual inspection and lacks the dynamic monitoring and early warning technique.In recent years,the structural health monitoring technique has been developed and maturely applied to structure of bridges,tunnels,ships and offshore platforms.However,the application research of structural health monitoring technique for stinger is still in the blank.On this background,this paper takes a deepwater pipelay vessel as an example to research and develop a set of structural dynamic monitoring and early warning system.It realizes real-time and scientific monitoring and early warning for stinger structure.In this paper,the overall design of the monitoring and early warning system is studied,the design principle of the system is defined,the selection of monitoring points is carried out,and the overall framework of the system is established.Then through the theoretical research and simulation calculation by SESAM software,the system function module is designed and researched,the calculation method reckoning non-measuring point stress based on the existing monitoring point stress is innovative proposed.Combined with the monitoring conditions at sea,the implementation plan of system is designed.The system software is tested,the test results shows that the system software is stable and accurate.Finally,time-domain analysis and spectrum analysis are studied on the basis of measured data of monitoring points.Time-domain analysis shows that the upper and lower chords of the stinger are the main stress members,the stress state of stinger is affected by laying tension,the phenomenon for roller uneven contacting is existed.Spectrum analysis determines the effective frequency range,distinguishes the dynamic force components of different frequencies.