Study On Optimal Sensor Placement For Prototype Monitoring System Of Torch Tower And Marine Riser

Structures with high slenderness have been more and more widely used in engineering, with the ratio of the slenderness becoming larger, the stability and safety problems have attracted more attention, therefore ensuring the structure safety and stable in service period is the key and difficult point in current engineering research field. However the simulation of the real environment has certain differences, and the slenderness structures have strong sensitivity of the environment load, causing structures damage accidents. The prototype monitoring system through real-time measurement of environmental information and the response of the structure, directly and accurately reflect the dynamic characteristics of structures, providing the realistic basis for the structure design, and the protection for the structure safety.Optimal sensor placement is the primary concern of prototype monitoring of large-scale structure. With the large scale of structures, a reasonable and effective sensor placement on the target structure can reduce the cost and improve the efficiency of the monitoring system. In this paper, optimal sensor placement is used for prototype monitoring of two structures, torch tower and marine riser, drafting the scheme of the sensor system. The main contents are shown as following:Firstly summarizing a variety of optimal sensor placement methods, the analysis of different methods emphasis is given, then choosing the method which combines the effective independence method and modal assurance matrix method applies to sensor placement of slender structure. According to the method, scheme can effectively recognize the structure, and the modal vector of structure can highly maintain the distinction.Through the modal analysis of the typical land high-rise structure, the torch tower, its vibration information can be achieved. Based on the modal information of torch tower, with the method which combines the effective independence method and modal assurance matrix method applied to the torch tower, the scheme of sensor placement of prototype monitoring for torch tower is formulated.Compared to the land high-rise structure, the fluid force on the marine riser cannot be ignored. Through the wet modal analysis which is based on added mass method, obtain the vibration information of structures in liquid. The vortex induced vibration is a representative phenomenon which reflects the ocean environment has great effect on the structures. Through the wet modal analysis of riser in steady fluid and unsteady fluid, make a conclusion of the current effects on the structures. Based on the wet modal information of risers, optimal sensor placement is used for prototype monitoring of risers in deep water.