The Distributed Strain Measurement of Dipole Superconducting Magnet Coil Based on OFDR Distributed Fiber Optic Sensor

In this study, a high spatial resolution distributed fiber optic strain sensing system, OFDR (optical frequency domain reflectometry), was used to monitor the strain of a dipole superconducting magnet coil during the cooling, excitation, and quenching processes. We studied the strain detection of the magnet structure using fiber optic strain sensors installed at different positions inside and on the surface of the magnet. The study shows that the strain results of the distributed fiber optic sensor at liquid helium were consistent with those of strain gauges with bridges. The distributed fiber optic strain sensing system can optimize the structural design of dipole superconducting magnets by detecting the global mechanical performance of the system. It can also indicate a comprehensive understanding of their mechanical behavior. The distributed strain sensing system will become an intelligent solution for detecting the strain of dipole superconducting magnets for structural health monitoring.