The Research Of Stress For The Leak Part In The Pipeline And The Application Of Fiber Bragg Grating Sensors

In recent years, because of the more and more frequent accidents of pipeline leakage, the research of pipeline leak detection put forward a new direction: improve the positioning accuracy, monitor the small leakage and guarantee for economic. The Fiber Bragg grating sensors can solve these problems well, but due to its high cost, reasonable layout must be conducted to reduce the number of sensors, safeguard its economical efficiency and maintainability.The paper focuses on the Fiber Bragg grating sensor layout, use Gaussian Model of the finite element analysis software of ANSYS, simulate the process of pipe welding and cooling. The research has shown that the residual stress value is greatest in seam welding. On the basic of mechanic of materials, study out the hoop stress formula and the axial stress formula of the ideal elbow under the influence of internal pressure load. By the research of the force of the ideal elbow and elliptical elbow under the influence of internal pressure loads and fluid loads, found that for the actual elbow, the maximum stress position tends to the neutral line of the elbow. Through the research, study out the hoop stress formula and the axial stress formula of the straight reducer and curved reducer under the influence of internal pressure load. The research of the force of the straight reducer and curved reducer under the influence of internal pressure loads and fluid loads, shows that the greatest stress of the straight reducer is located in the big port. But as for the curved reducer, the greatest stress is located in the entrance of the big end inside the arch. The experiment results is conformed to the theoretical formula. Introduce the sensing mechanism of temperature and strain of the Fiber Bragg grating. By applying a butyl rubber synthetic polymer to the Fiber Bragg grating sensing probe for monitoring the hydrocarbons, solve the problems of “cross sensitivity” of temperature-strain effectively. At last, apply the results of this paper to the Fiber Bragg grating sensor in piping layout, as a guide for the actual construction.