Optical Fiber Sensor In The Structure Of The Detection Applied Research

Fiber bragg grating sensor is a new sensing technology, and the diagnostic technology to the structure of stress loss in prestressing strand is the tendency of major projects in damage detection. The close integration of these two technologies makes the structure of long-term monitoring and complete diagnosis become possible. So it’s significant project to apply the fiber bragg grating sensor into the research on major engineering structures, the monitoring and detection on the loss of prestress in prestressed concrete structure and structural health monitoringExperiment and theoretical analysis taken in this project:It produces the φ15.2composite intelligent teel material for the characteristics of different fiber bragg grating strain sensors and strain transfer theories. And it takes the relevant mechanical test to check it’s mechanical property, including mechanical repeatability of the composite intelligent steel, the sensibility and reliability of the strain and the stress relaxation performance of composite intelligent steel strand. This new material can be put into use after test. This article produced the3.4m long unbonded prestressed concrete beam component and use the Prestressed strand of optical fiber sensing composite intelligent steel strand prepared in advance. The composite intelligent steel monitors the whole process of the stress loss of the unbonded prestressed concrete beam by the optical fiber mediation instrument to analyze wavelength, strain changes and the surface of the paste resistance strain gauge of unbonded prestressed concrete and fiber bragg grating sensors. It uses the bending test of the prestressed girder to analyze the difference between the calculated value and the measured value of the strain to verify that the fiber bragg grating sensor is more exact and favorable than the traditional electric resistance strain gauge. Then, it takes the finite element numerical simulation analysis software MIDAS Civil to monitor the stress loss of prestressed steel strain in flexibility of the unbonded prestressed concrete beam and builds the relevant analysis model. It reaches the result by computers and makes an approved idea that the fiber bragg grating sensor is more exact and favorable than the traditional electric resistance strain gauge by analysis of those. And it improves structural health monitoring and verifies the application in testing technology of civil engineering. Finally, it concludes what advantages the fiber bragg grating sensor and the Prestressed strand of optical fiber sensing composite intelligent steel strand have and how important both of them are in civil engineering.