| Corrosion of steel in concrete was a major cause of structural deterioration, which had became one of the most important aspects in structural health monitoring (SHM). Hence, a low-coherence optical fiber sensing system (LCFS) based on Michelson interference was developed to monitoring steel corrosion in concrete, which can achieve the resolution in the scale of micro-meter. However, the scanning optical path of this system was very short, and how to rapidly and accurately match the sensing fiber length should be addressed. Also, environment and distance from the monitoring sites to the laboratory limited engineers to operate the system and obtain the data easily. Hence, in this thesis, optimizations of LCFS have been done to. solve the mentioned problems.Laser ranging has many merits, such as small volume, light quality, high precision, wide measurement range and strong anti-jamming capability, etc. This thesis introduced several principles of laser ranging and a comparison was given. To reach the requirements of the measurement time, precision and resolution, laser phase ranging method was chose to measure the length of the fiber, which can match optical fiber length quickly and easily. It proved that this method had the feasibility and practicability through the experiments.Remote control was based on the computer technology to complete control and maintenance of the network status and remote equipment through the network communication system. This thesis proposed a technique based on Lab VIEW communication, which was based on the transmission control protocol/internet protocol (TCP/IP) communications protocol and Web Server technology to carry out a remote interface in order to adjust the parameters remotely and realize data transmission. The experimental test demonstrated that this design can conveniently set the operation parameters, transmit data stably and meet the requirements of the long-term corrosion monitoring. |
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