We present the design and first results of an assembly that enables rare earth barium copper oxide (REBCO) superconducting cables—the VIPER cable in this work—to be tested in the SULTAN facility under the simultaneous application of transverse electromechanical loading and axial mechanical strain. The objective is to emulate the loads that a REBCO cable would experience in a three-dimensional coil but in shorter and simpler straight cables, reducing the cost, schedule, and complexity of high-fidelity conductor qualification. The assembly uses two methods for inducing axial strain in the cables. First, hydraulic jacks stretch the assembly and inserted Invar shims lock in up to ∼0.3% axial cable strain on the benchtop at room temperature. Second, the different coefficients of thermal expansion between Invar clamps and the copper cable are exploited to induce an additional ∼0.3% axial strain on the cable when the sample is cooled in the SULTAN test well from room temperature to below 50 K. Finite element analysis modeling shows that the soldered matrix of the VIPER cable transfers approximately 50%–60% of the external cable strain into the REBCO stack. The assembly was successfully employed at SULTAN, enabling two VIPER cables to be cycled 500 times at 382 kN m⁻¹ transverse electromechanical loads with ∼0.5% mechanical strain on the cable (corresponding to ∼0.3% mechanical strain in the REBCO stacks) demonstrating critical current degradation stabilizing after 30 cycles at less than 5% and providing confidence in VIPER cables under realistic high-field magnet conditions.

中文翻译：

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SULTAN 设施中 REBCO 电缆测试的同时横向载荷和轴向应变

我们展示了一种组件的设计和初步结果，该组件使稀土氧化钡铜 (REBCO) 超导电缆（本研究中的 VIPER 电缆）能够在同时施加横向机电载荷和轴向机械应变的情况下在 SULTAN 设施中进行测试。目的是模拟 REBCO 电缆在三维线圈中会经历的负载，但在更短和更简单的直线电缆中，降低高保真导体鉴定的成本、进度和复杂性。该组件使用两种方法在电缆中引入轴向应变。首先，液压千斤顶拉伸组件并插入殷钢垫片，在室温下在工作台上锁定高达 ∼0.3% 的轴向电缆应变。第二，当样品在 SULTAN 测试井中从室温冷却到 50 K 以下时，因瓦夹具和铜电缆之间的不同热膨胀系数被用来在电缆上引起额外的 ∼0.3% 轴向应变。有限元分析模型显示VIPER 电缆的焊接矩阵将大约 50%–60% 的外部电缆应变转移到 REBCO 堆栈中。该组件已在 SULTAN 成功使用，使两条 VIPER 电缆能够在 382 kN·m 下循环 500 次⁻¹横向机电负载，电缆上有 ~0.5% 的机械应变（对应于 REBCO 堆栈中的 ~0.3% 机械应变），表明临界电流衰减在 30 个循环后稳定在小于 5%，并在现实的高电压下为 VIPER 电缆提供信心磁场条件。