The Design And Demodulation Research In Two-Dimension Dynaminc Deformation Measurement System Base On FBG Sensor

Fiber Bragg gratings have already expanded their application in field aviation, ships, radar and other high-tech devices from traditional bridges, dams and infrastructure, owing to its proper features. In recent years, the application of Bragg grating mainly focused on single-point or multi-point measurement which is means of discrete quasi-distributed measurement. In the field of structural health monitoring, damage localization and material safety fatigue assessment, it is essential that the two-dimension material’s surface measurement using distributed sensing technology. Discrete quasi-distributed method cannot satisfy the application requirement. Thus, it is a key question need to be solved for development of intelligent materials that achieving two-dimensional surface parameter measurement by means of FBG sensors and proper algorithm.In this dissertation, we demonstrated a two-dimensional strain measurement system based on FBG strain sensors. The system combine with Computer processing center and a data acquisition card utilizing dispersive grating demodulation method interrogated the strain distribution in two-dimensional surface of glass fiber plate laying FBG sensors network. The feasibility of measurement method and fit demodulate program were investigated. The main content includes:Base on dispersive grating demodulation method, the construction and program design of two different algorithms searching peak value used to demodulate optical grating center wavelength was complete in the LabVIEW virtual instrument platform.We describe the principle of two-dimensional surface strain measurement based on FBG sensors. The measurement system of one-dimensional cantilever and two-dimensional was constructed. The analysis of key technologies in measurement system, such as Bragg grating temperature-insensitivity technology,1×8optical switch driver, synchronous data sampling and others were made and the solution was given.Meanwhile we design the algorithm which utilizing the FBG sensors center wavelength information to achieve two-dimensional strain distribution and visualization. The final result demonstrates that two-dimensional strain measurement systerm we present could correct sample strain signal from FBG sensors network, then demodulation was carried by effectively utilizing program we have written and acquire real-time two-dimensional strain information of plane to be measured. It can satisfy the demand of two-dimensional strain measurement.