Fiber Bragg Grating Dual-material Vibration Non-inductive Temperature Sensor Design

Fiber optic sensing technology is a new sensing technology developed from fiber optic and fiber optic communication technologies.The sensing sensitivity of fiber optic sensors is several times that of traditional sensors,and it can continue to operate in harsh environments such as high voltage,high temperature,high noise,and strong corrosion.Two-material vibration-insensitive temperature sensors based on fiber Bragg gratings(FBG)are an important class.In this thesis,the dual-material vibration non-inductive temperature sensor based on fiber grating is studied.Aiming at the existing design scheme and the problem of temperature-sensing material,a dual-material cantilever beam sensor structure based on temperature sensing material is proposed.Compared with the existing sensor structure,the scheme is simple in structure,easy to process,high in measurement accuracy,and has broad application prospects.Fiber Bragg gratings can be used for temperature detectors in a wide temperature range.Measurements of various temperature signals can be reflected in the spectral effects of fiber gratings,such as the expansion and contraction of the response material on the sensor,changing the period of the FBG,and the resulting central wavelength.The offset corresponds to the expansion and contraction of the responsive material,and the mechanical properties of the material can be indirectly known by testing the spectral properties of the FBG.The traditional FBG temperature sensor,the ordinary FBG is directly mounted on a single metal material,when the temperature changes and the external vibration will be FBG stretching,the test results are doped with the influence of vibration factors,so that the sensitivity is reduced.The vibration-insensitive temperature sensor designed in this paper focuses on the adjustable sensing sensitivity.The fixed base and cantilever beam are designed by CAD software.The ordinary FBG is mounted on the cantilever beam composed of two different kinds of metal materials,using ultraviolet glue and structural glue bonding.Brass and aluminum.The physical properties of the two metal materials are quite different.Due to the different Young's modulus and thermal expansion coefficient of the two materials,the two metals of the cantilever are affected by temperature.Different stress extensions occur,and the amount of stretching of the two FBGs is different due to different material properties.Even in the environment with severe vibration,the cantilever beam has the effect of canceling the vibration on the FBG.The reflected wavelength contains two reflection peaks of different wavelengths,and the reflection peak is measured to achieve the purpose of vibration non-inductive measurement.Compared with traditional FBG sensors,the sensitivity has been significantly improved.