Mechanism And Experimental Study Of FBG Strain Transfer

With the development of Fiber Bragg grating(FBG)sensing technology,FBG sensor is widely used in the structural strain monitoring due to its high sensitivity and anti-electromagnetic interference.FBG strain transfer equation is the theoretical basis for the practical application of the sensor,including sensor package design,sensitivity coefficient calibration and optimization design,reflecting the mechanical coupling mechanism between the fiber grating material and the matrix material.In this paper,the main research is the strain transfer analysis of two-point sticking FBG sensor.Firstly,the author derives strain transfer of two-point sticking FBG sensor.Secondly,On the basis of formula,the author analyses wide range FBG strain transfer theory and sensor optimization design.etc,including:(1)By designing two-point sticking FBG sensor,On the basis of shear-lag theory and the stress analysis of fiber and adhesive micro,the two-point sticking FBG sensor strain transfer rate and average strain transfer rate formula are derived.It concludes that two-point sticking FBG strain transfer rate is equal to the fiber average strain transfer rate.(2)Wide range FBG strain transfer rate formula is derived.The author plot the distribution curve of the strain transfer rate of two-point sticking FBG strain sensor,drawing curves of different gauge distance and layer thickness,having analysis of the effect of different parameters on the strain transfer rate.(3)Based on the theory of two-point sticking FBG sensor strain transfer,FBG sensor is optimized,including the best adhesive bonding length assume two-point sticking FBG strain transfer more than 90% and the best adhesive shear modulus based on mean square deviation decision method.(4)Calibration test of packaged FBG and bare FBG sensor is required.It compares theoretical and test strain transfer value of two-point sticking FBG sensor.Finally,On the basis of two-point sticking FBG strain transfer theory,clamp type FBG sensor is designed in the application of dynamic monitoring of Shengjing Cultural Art Center.Strain transfer analysis of two-point sticking FBG sensor has innovatively enriched the theory of FBG sensor strain transfer.It provides theoretical basis for FBG sensor sensitivity coefficient calibration,FBG sensor optimization design,the new experimental calibration method.