The Research And Application Of Fiber Bragg Grating Sensors On The Structure Of Angle Steel For The Health Monitoring Of Electric Tower

FBG sensors are a type of optical fiber sensors with the characteristics of low cost,good linearity,wavelength multiplexing capability and resistance in harsh environments,which have been used in civil structures,aircrafts,oil pipelines,etc.For experiments in Labs,FBGs could be mounted on the structures by expoxy directly without extra packaging scheme or even embedded in the structures during the design process of the structures.However,it is difficult for FBGs to monitoring the existing structures without proper packaging because it is impossible to embed the FBGs and unacceptable to mount FBGs on the structures directly for the requirements of long term and stability.How to package FBGs and install the packaged FBG sensors become key issues for engineering applications.Overhead transmission lines consist mainly of support towers,conductors,insulators and ground wires.High voltage towers are the important part for power transmission needed to be monitoring in real time.Firstly,this paper builds the model of the fiber Bragg grating sensor packaged by fiber reinforced polymer,analyzed the influence of strain transfer of the FBG sensor by the thickness and the length of the fiber reinforced polymer.The results show that the greater the thickness,the higher transfer coefficient,the lower sensitivity.In the case of the same thickness,the length has almost no effect on the transfer coefficient.Secondly,this paper builds the model of installation position and installation method of fiber Bragg grating sensor,analyzed the influence of strain transfer of the FBG sensor by the different installation position and installation method of the sensor on the angel.The result shows that the difference of the installation location will lead to the great change of the measurement data,and the changes of the support structure will lead to the large change of the measurement data.Then,we use a fiber Bragg grating sensor packaged by fiber reinforced polymer to measure the strain of an angle steel.The experimental results were in accordance with the simulation results.A new installation scheme is proposed to measure the multi-dimensional strain at the same time.Finally,we show the measured data on the towers,and the data for long-term and galloping are analyzed.