Study On Strain Transfer Characteristics And Package Technology Of Fiber Bragg Grating Sensors For Safety Monitoring Of Underground Engineering

The sensor based on FBG is an important monitoring unit for structure propertiesmeasurement. With Its quasi-distributed, corrosion resistance, simple structure, stronganti-jamming capability, convenient to form network, stable long-term performance,FBG’s sensor has become an important development direction of safety monitoring forunderground engineering structural.With the background of underground engineering structural safety monitoring,strain transfer model of the three-layer adhesive structure package was proposed byknowledge of mechanics of materials. The package length, the package thickness,elastic modulus, Poisson’s ratio of package material which affect strain transfer wereanalyzed. The affecting factors also were calculated by the method of finite elementanalysis. Results of calculation were basically accordant to the theoretical analysis.Some related experiments were done to verify the theory. The analysis results of the twoprovide an important basis for the guidance of engineering package.The innovation of the paper is lay on: by the way of theoretical calculation andfinite element analysis, the package length, the package thickness, elastic modulus,Poisson’s ratio of package material which were affected strain transfer were analyzed.The package length and the thickness were critical factor, and the influence of elasticmodulus of material was smaller than that two factors. The influence of Poisson’s ratioof package material is smallest. With different package length, transfer efficiency curveof same length of fiber Bragg grating was obtained. By the experiments of cantileverstructure, strain characteristics of two kind’s fiber Bragg grating sensor were carried outto verify the theoretical analysis and numerical calculation of influence.