DEVELOPMENT OF A CRYOGENIC FATIGUE TEST FACILITY FOR HIGH TEMPERATURE SUPERCONDUCTING TAPES

Because of the high critical current density in the intense magnetic field, wider temperature margin, resistance irradiation and good mechanical properties, high temperature superconducting tapes (BSCCO and ReBCO taps) have a huge potential application in accelerator magnets, high field magnets and superconducting electric power systems. Some expectable opportunities will be created for modern high-tech electromagnetic equipment. High temperature superconducting tapes with substrate layers usually have high tensile strength. Thus, they can be applied under an intense electromagnetic field. However, in its application process and under the operation conditions, many kinds of inevitable fatigue loads will occur, which have an impact on the current-carrying capacity of the high temperature superconducting tapes and can destroy the high temperature superconducting magnets. A cryogenic fatigue test facility for high temperature superconducting tapes is introduced, the system can be used to measure the mechanical, thermal and strain-field-dependent behaviors of fatigued superconducting wires and tapes under variable cryogenic temperatures. Based on the cryogenic fatigue test facility, the mechanical behaviors and current-carrying characteristics of tension-compression fatigued YBCO tapes were experimentally studied. The preliminary test results show that their mechanical behaviors and current-carrying characteristics showed a nonlinear dependence on the stress ratio during the fatigue test. The successful development of the cryogenic fatigue test facility will provide a basic fatigue test platform for the design and development of accelerator high temperature superconducting magnets.