Study Of Strain In Superconducting Magnet By Fiber Bragg Grating And Numerical Simulation

This paper carries out the research on the influence of the strain and stress on the magnet performances. In the cryogenic and high magnetic field environment, Fiber Bragg Grating strain sensor has many advantages compared with the conventional electrical strain gauges to measure the strain of the magnet. The principle of the Fiber Bragg Grating is discussed in detail. The experiment demonstrates that the FBG can work normally under the liquid nitrogen temperature.In order to get the curve of stress, strain and wavelength in the circumstance ofthe cryogenic and high magnetic field, the △λ-με relationship is studied throughthe principle of the cantilever. Multi wave crest was seen in the first experiment .The second experiment culminates in the relation of strain and the shit of the Bragg wavelength, which shows FBG can work normally under liquid nitrogen in good liner.The curve of △λ-με is given, and the function of the △λ-με is introduced.In order to simulate the magnet precisely, a detailed finite element model is created. The elements of the tapes and resin of the magnet are treated respectively in this model. The stress and strain of the magnet are plotted in different operating currents. According to the demarcation experiment result the strain of the magnet at different operating currents is measured using the Fiber Bragg Grating strain sensor.This paper illustrates that the FBG strain sensor is a perfect utensil to measure the strain of the high temperature superconducting magnet, and the combination of finite element simulation and FBG to analysis the strain of the high temperature superconducting magnet is an efficient approach.