Research On Corrosion Monitoring Sensor In Weak Acid Environment Based On Optical Fiber SPR Effect

In recent years,the early corrosion of metal materials by natural environment,especially weak acid environment,has attracted more and more attention.Optical fiber corrosion sensor is an improved corrosion detection device based on the traditional optical fiber sensor,which is used to collect or transmit corrosion information.With its simple structure,high integration,strong sensitivity and real-time monitoring,the optical fiber corrosion sensor has become a research hotspot in the field of corrosion monitoring.In this paper,based on summarizing the basic detection methods of optical fiber corrosion sensor and the research status at home and abroad,a variety of optical fiber corrosion sensor sensitization schemes are designed.After comparative analysis,the sensitization scheme based on optical fiber surface plasmon resonance effect is selected for research.The experimental system is built to monitor the corrosion of the sensor.The main contents of the paper include:Firstly,the corrosion mechanism of metal in weak acidic environment was studied.Based on the detection principle of optical fiber corrosion sensor,a variety of sensor sensitization schemes are designed and theoretical derivation was carried out.The surface plasmon resonance effect of nano metal is introduced,and the influence of metal film thickness on surface plasmon resonance effect is analyzed theoretically.Then,the theoretical model of optical fiber corrosion monitoring based on surface plasmon resonance effect is studied.The surface plasmon resonance effect of optical fiber coupling structure is analyzed by numerical calculation and finite element simulation.The influence of optical fiber transmission mode,metal film length and thickness on the resonance spectrum of the sensor is explored.The appropriate sensor structure parameters are determined.The sensor structure based on optical fiber core-offset splicing is proposed and simulated.Finally,the core-offset splicing fiber corrosion sensor based on surface plasmon resonance effect was prepared.The experimental platform was built to analyze the evanescent field enhancement effect of different dislocation optical fibers.The relationship between corrosion time and resonance spectroscopy is analyzed.