| With the development of economy, improvement of people's working and living conditions is a urgency assignment . So developing intelligent buildings is considered now. We can imbed sensor elements and drive elements in the material and architecture with its production. The sensor elements can measure and monitor the structure's state parameter real-time, such as stress, strain,temperature and damage. And drive elements can regulate and control the structure's state, then they can assure the structure's safety operating and keep the structure in the best state all the time. Fiber-optic strain sensor can modify the classical electrical measurement's defects and limitations and have its good attributes, so it gets a extensive application in testing mechanics, strain analysis and safety detection of the structure.Based on analysis of domestic and foreign study actualities on fiber-optic strain sensor-based system, a new winding fiber-optic strain sensing technique based on OTDR is presented. The mainly research consents of the paper are as follows: We analyze the fiber's loss of the winding fiber-optic strain sensor-based system in theory, and establish the mathematical model of the winding fiber-optic's loss. We design a distributed fiber-optic strain measurement system based the winding scheme, and research the influencing factors of the initial loss generated in the fiber spiral twisted sensing-process in theory and experiment. Then we get the related curves. We also analysis the property requirement of sensing fiber-optic, the sensing spots'layout program and the estimation of the maximal number. The experiments study the different winding diameters and thread pitches'effect on the fiber-optic's sensing sensitivity, and we operate the experiment on the sensor's repeatability.The research results indicate that the designed fiber-optic strain sensing system has the good linearity and repeatability, and provides the theoreticalbasis to the application in the civil engineering. |
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