Application Of Fiber Bragg Gratting Sensoring Technique In Safety Monitoring Of Ocean Engineering

With the further development of marine oil and gas resources, higher requirement to the performance of ocean engineering structure is necessary; more attention has been paid to the safety issue of ocean engineering under complicated marine environment. Accordingly, some experts proposed the concept of safety monitoring on ocean engineering structures. First of all, it can evaluate the design model and related criterion of marine structures, which can provide rational support for structure reliability optimization design; then it can forecast and alarm any sudden disaster, which ensuring a safety environment for the running of ocean engineering structure.As the specificity of safety monitoring on ocean engineering structures, it needs the sensors, core part of the sensing system, to be waterproof, moisture-proof, stability long-term running, real-time monitoring to work under a complicated marine environment. However, most of the traditional electricity sensor, can't theoretically meet those requirements. A program that Fiber Bragg Grating (FBG) sensing technique has been proposed. Consequently, specific research about the application of FBG works in safety monitoring of ocean engineering structures has been done in this paper.This paper has been divided into 5 parts to study the sensing technique and engineering application of FBG.In the first part, it mainly introduces the sensing technique of FBG and summarizes main research contents from project background.In the second part, it analyses the FBG sensing technique theoretically, mainly contains introduction of fiber bragg structure, optical transmission principles, and FBG strain and temperature test principles. It also discusses the theory researches and application status in and abroad about FBG.The third part focuses on researching FBG sensors based on laboratory. It introduces the experimentations of static strain measurement in the uniform beam and dynamic strain measurement in the simple beam. Then it analyses the FBG sensoring characteristic from the results.The fourth part is about the application of FBG in some structure model experiments, including the ice load model experiment and flexible pipes steel strain measurement experiment. The results indicate that FBG is unparalleled in strain measurement under special circumstances or structure.The fifth part is the most important point of this paper. It focuses on the application of FBG in ocean engineering structure in situ. FBG used in the program of ice load long-term measurement on the platform in Bohai Sea in winter is primarily introduced, and then the strain measurement on the yoke of Bohai MingZhu FPSO. The successful application results that FBG can long-term work under a harsh environment, which means it can be used in real-time safety monitoring in ocean engineering structure. Finally, it discusses the application of FBG in deep-sea engineering structure, and brings forward that FBG has a huge potential in the application of Deep-sea engineering structure.The last part is a summery of the paper, also a prospect of the research development of FBG monitoring technique.