Study On Principle Of Surface Adhesive For Fiber Bragg Grating Sensor Monitoring And Its Experiments

Because the mineral engineering hazard has the characteristics of complexity,ambiguity and burstiness, it needs further development of the sensing technology. Optic fibersensor is playing an important role in rock deformation monitoring.Fiber Bragg grating sensoris a new type of high performance sensor. Based on the strain transfer of surface FBG sensorwas analyzed. The strain transfer was analyzed when the surface FBG sensors were sticked tothe rock sample, round steel bolt and plane deformation model. It is significant for increasingour knowledge level of the mechanics action and the application of the FBG sensor.In this paper, based on the FBG’s sensing properties, under the consideration of themodulus of elasticity of the host material,the strain transfer of the bare FBG was analyzed.Thestrain transfer coefficient was got and compared with one which the bare FBG was buried inthe shallow slot of the host. The mechanics model of the substrate packaged FBG strainsensor was constructed, the strain transfer was analyzed and the strain transfer law wasobtained.Under the consideration of the modulus of elasticity of the host material,the factorsinfluencing strain transfer ratio of FBG stain sensor were analyzed.Considering the factual need, the copper substrate packaged FBG strain sensor had beendeveloped and their sensing properties were investigated experimentally.Two groups of uniaxial compression tests on rock samples were launched,one of whichhad the bare FBG and ESG,the other one had the copper substrate packaged FBG sensor andESG. The strain transfer coefficients were got when the bare FBG and the copper slicepackaged FBG sensor were sticked to the rock samples.The result shows that both of the bareFBG and the copper slice FBG sensor can be used in the rock deformation monitoring.In order to simulate the forces of coal mine tunnel anchor bolts, three bare FBG sensorswere placed along the bolt to measure strain and three ESGs were placed adjacent to the fiberoptic sensors.The pullout test was made to got the strain transfer coefficients of the bare FBGsticked to the round steel bolt.The result shows that the axial stress got by Gaussian function fit is nearly the fact. The parameter t of the Gaussian function is related with the grip abilityof the rock.In order to analyze the strain transfer of the copper slice FBG sensor, the copper sliceFBG sensors, the vinyl acetate tube FBG sensors and the stainless steel tube FBG sensorswere placed in two plane simulation models.The size of the two models were0.5m×0.5m×0.14m and3.0m×1.33m×0.2m and the dial indicators were placed correspondingto the FBG sensors.The strain transfers of the three sensors were got.The result shows that thefit between the slice packaged FBG sensors and the model is better than between the tubepackaged sensors and the model.The bare FBG sensors and the slice FBG sensors are applied in rock sample test,boltpullout test and plane simulation model.The train transfer coefficients of the bare FBGsensors and the slice FBG sensors are got and compared with the coefficients in theory. Thetest result validates the established transferring model of surface pasting.