System for characterizing the electromechanical properties of REBCO coated conductors through simultaneous measurements of critical current and mechanical load

Abstract

Abstract Various test techniques have been established to investigate the electromechanical properties (EMPs) of coated conductor (CC) tapes under external loads. The most conventional method is to examine variations in a critical current, I c, by repeatedly measuring the V–I curves while intermittently applying a load or deformation to the CC tape. Conventional methods for obtaining EMPs, such as the reversible limits for I c degradation, require repeated measures of I c in a loading–unloading scheme, and this entails considerable time and effort, therefore, they must be improved for practical and engineering reasons. We recently developed an easy-to-use system that can continuously measure variations in I c while applying a load or deformation to the CC tape, thereby evaluating its EMPs. The main advantages of the new measurement system are real-time monitoring of I c behaviors during loading and allowing reduced the test time. While it uses a conventional test configuration, this new system continuously measures I c through effective feedback control of the electrical-field voltage induced in the CC tape specimen during loading. Through this feedback control system, the I c degradation behaviors in CC tapes resulting from possible cracking in the superconducting layer during loading are depicted. The reversible limits for I c degradation were also determined. To assess the effectiveness of this newly developed measuring system, the applicability of the method was identified by evaluating the EMPs of various commercially available CC tapes. By comparing the results with those achieved using conventional testing, we found this to effectively evaluate the EMPs of CC tapes. The results showed that this system provides a simple way of evaluating the EMPs of high-temperature superconductor CC tapes by simultaneously measuring variations in I c under load or deformation. It is much faster at depicting I c degradation behaviors, and it elaborately determines the reversible limits of I c induced in the CC tape during testing.