Experimental Study on Strain Measurement in NbTi Superconducting Coil Structures Based on Symmetrical Compensation Bridge

The strain measurement technology of resistance strain gauges has been widely used in various types of superconducting magnets. Based on electrical signal transmission, the resistance strain gauges and electrical signal lines will be affected by temperature and electromagnetic field, which will cause interference in strain measurement. Therefore, it is challenging to make high-precision measurements using resistance strain gauge measurement technology. To improve the measurement method, the symmetrical compensation bridge is proposed to compensate for the influence of temperature gradient and magnetic field noise. This method is verified in the temperature and electromagnetic changing field during cooling and excitation processes on the NbTi superconducting magnet. The results show that the symmetrical compensation bridge can further reduce the error caused by wire resistance and environmental noise strain measurement in variable temperature and strong magnetic field environment. The proposed compensation bridge can enrich the strain measurement method in extreme environment, and provide an important strain detection method for the testing and operation of superconducting magnet structures.