Key Technique Of Dynamic Surface Measurement And Visualization Based On FBG Sensing

Surface measurement and visualization with embedded sensor network is one of the researches for structural health monitoring. The key technologies and methods could be applied to real-time structural health monitoring such as the solar array measurement of aircraft and the plane airfoil in haste flight. It would also have potential applications for to the health monitoring and visualization of civil structures, such as dams, bridges, high building and dome.This dissertation presented a novel solution with the fiber Bragg grating (FBG) sensor network as the sensing unit which has excellent sensor and structure characteristic; based on the design of sensor network, a dynamic shape measuring system are built to reconstruct the flexible surface shape and built by visualization impaction to this problem. First, the scheme of the system has been analyzed and the FBG was selected as the sensor in the system and built a large sensor network with the technology of the Spatial-Division-Multiplexing (SDM) and the Wavelength-Division-Multiplexing (WDM). According to the result of surface finite element analysis (FET), the FBG sensors were distributed on the maximum amplitude locations of movement. The processing of packaging includes that selecting the glue-water near the surface material, design of high intensity packaging, and realization of quick response and lower effect to the vibrating system. The dissertation presented a reconstruction algorithm from curve reconstruction to surface reconstruction according to the curvature and arc length information. This proposed algorithm first reconstructs surface slices and joint the slices. By displaying the reconstructed visualization effect, the real-time deformation information and essence of movement can be well monitored.A tested has been designed to simulate the lower-frequency movement of the solar array. The multi-modules shapes could be measured which can be used to prove the design. The testing result has been estimated to the measurement and the error has been analyzed. In order to improve the measurement and reconstruction precision of the system, some methods and steps are also presented to reduce the errors, thus provides technique preparation and for ongoing research.The main contributions of this dissertation are as follows:(1) Setup a set of real time measurement and visualization system consisted of embedded sensor network, flexible surface structure, FBG demodulation device and computer for surface measurement. The computer visualization is an important improving for the traditional structural health monitoring.(2) Presented a reconstruction algorithm from curve reconstruction to surface reconstruction based on the curvature and arc length information. A novel algorithm that first reconstructs surface slices and joints the slices also was proposed based on the curvature and the arc information which was not well solved in the differential geometry discipline.