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High-temperature superconducting (HTS) rare-earth Ba2Cu3O7−x (REBCO) coated conductors (CCs) have significant potential in high-current and high-field applications. However, owing to the weak interface strength of the laminated composite REBCO CCs, the damage induced by the thermal mismatch stress under a combination of epoxy impregnation, cooling, and quenching can cause premature degradation of the critical current. In this study, a three-dimensional (3D) electromagnetic-thermal-mechanical model based on the H-formulation and cohesive zone model (CZM) is developed to study the critical current degradation characteristics in an epoxy-impregnated REBCO CC caused by the damage during a quench. The temperature variation, critical current degradation of the REBCO CC, and its degradation onset temperature calculated by the numerical model are in agreement with the experimental data taken from the literature. The delamination of the REBCO CC predicted by the numerical model is consistent with the experimental result. The numerical results also indicate that the shear stress is the main contributor to the damage propagation inside the REBCO CC. The premature degradation of the critical current during a quench is closely related to the interface shear strength inside the REBCO CC. Finally, the effects of the coefficient of thermal expansion (CTE) of the epoxy resin, thickness of the substrate, and substrate material on the critical current degradation characteristics of the epoxy-impregnated REBCO CC during a quench are also discussed. These results help us understand the relationship between the current-carrying degradation and damage in the HTS applications. [ABSTRACT FROM AUTHOR]

The second-generation high-temperature superconducting (HTS) coated conductor has been recognized as one of the most promising materialsfor high field magnets due to its superior electromagnetic and mechanical performances. HTS racetrack coils wound with the coated conductors are an extensively used configuration in engineering applications, such as HTS machines and high-speed maglevs. In this paper, in order to analyze the electromagnetic and mechanical behaviors of HTS racetrack coils, a 3D coupled electromagnetic-mechanical model is used to consider the effect of coil deformation and the strain dependence of critical current. The effectiveness of the coupled model is validated by comparing the numerical results with experimental data in the literature. A numerical simulation of a 3D HTS racetrack coil subjected to an external electromagnetic field is carried out using coupled and uncoupled models. The results indicate that the structure deformation can reduce the penetration depth of the screening current, and the hoop stress and strain are mainly concentrated on the circular part of the racetrack coil. Afterwards, the influences of various parameters on the electromagnetic and mechanical responses of the HTS racetrack coil are also investigated. [ABSTRACT FROM AUTHOR]