Research on novel pressurized fiber Bragg grating static level based on circular structure

The static levelling system has significant value in the settling measurement of the structures. A novel pressurized static level based on circular structure is designed by using fiber Bragg grating (FBG) sensing technology in this research. The variation of the level pressure in the connecting vessel can be transmitted through the diaphragm to the FBG of the circular ring. The Ritz method is used to calculate the lateral deformation of the circular ring under the concentrated force, constructing the theoretical sensitivity model of the sensor. Further, finite element simulation and static experiments are applied to modify and verify it. According to the experimental data, two FBGs arranged horizontally along the circular ring, multiplying the sensitivity of the FBG static level to about 4.75 pm/mm, while the resolution can reach 0.02 mm. In addition, the temperature compensation of the sensor can be realized by the synergistic change of the measurement point and the reference point within the system of connecting vessel.