Fiber Grating Pressure Sensor And Its Applications In The Dynamic Weighing System

The technology of weight-in-motion (WIM) is an effective measure to prevent overrunning and overload, safeguard highway and bridge, decrease traffic accident. WIM is also the foundation to realize modernization of traffic and transportation management, which will provide critical contributions to the society and the economy.In this study, in the first chapter, we present an introduction of WIM. Within these discussions, we conclude that the research and development of WIM technology is very important.In the second chapter,The principles and methods of existing WIM are briefly analyzed. We also give comparisons of performance, price of installment and maintenance of several kinds of WIM equipments. We present the discussions and analyses of the new sensing component using fiber Bragg gratings (FBGs), which has attracted wide interest and extensive studies. The application of FBG in communications and sensor fields is simply introduced, while the advantage and defect of FBG in sensor field is simply analyzed.In the third chapter,we emphasize the analysis of the properties of strain-model of sensors and detecting method of fiber Bragg grating. This part is the basis for our WIM technology and model design, as well as related experimental investigations.We then present the descriptions of our approaches for designing a new WIM system based on above analyses, using the combination of fiber-reinforced composites (FRC) and fiber Bragg gratings. The unstrained FBG center wavelength in our system is 1536.770 nm, and the FBG is epoxied on one of the FRC laminates and more FRC laminates were epoxied onto either side evenly until the sensor thickness reaches 1 centimeter. To protect the sensor and improve its flexible strength, the sensor was put into a plastic pipe and completely filled with epoxy until no air exists inside the pipe. After the epoxy is cured, the sensor becomes solid and strong.In the fourth chapter ,the experimental results show that FRC WIM sensor has much larger dynamic range and higher sensitivity than metal-based WIM sensors, and the minimum resolvable weight of FRC WIM sensor can be as low as 1.3 kilograms.In summary, in our study we have investigated the WIM technology and system designin both theoretical and experimental approaches. The experimental results and comparisons...