Axial tensile, transverse compressive and bending strain experiments on Bi(2223)/AgMg single core tapes

Goldacker, W.; Kessler, J.; Ullmann, B.; Mossang, E.; Rikel, M.O.

doi:10.1109/77.402937

Cited by 41 publications

(13 citation statements)

References 4 publications

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“…The single tapes are bent using a bending device developed by Goldacker [30,31]. The device can continuously bend the sample at low temperature (T=77 K), enabling a high resolution in bending radius without the need for thermal cycling.…”

Section: Methodsmentioning

confidence: 99%

Bending properties of different REBCO coated conductor tapes and Roebel cables atT= 77 K

Otten

Kario

Kling

et al. 2016

Supercond. Sci. Technol.

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Application of REBCO coated conductors in coils or cables involves deformation of the conductor in different modes, such as in-plane bending, out-of-plane bending and torsion. For example, the dipole magnet designs in the EuCARD-2 project require bending radii as low as 7.5 mm, inducing significant bending strain in the REBCO layer. In this paper, we investigate the effect of out-of-plane bending on the current-carrying properties of coated conductors from different manufacturers. The samples are manipulated by means of a Goldacker-type bending rig, which allows continuous bending at T = 77 K. By reversal to after each bending step, the reversible strain effect is separated from irreversible degradation. All tested conductors are found to tolerate compressive bending to a radius of 6 mm with less than 5% irreversible degradation of the critical current. The magnitude of the reversible strain effect shows a large variation among the samples. The effect of out-of-plane bending on Roebel cables is investigated as well, and the results are compared to the bending characteristic of single conductors. The results show no detrimental effect of the cable assembly on the bending properties within the constraints of the test.

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Section: Methodsmentioning

confidence: 99%

Bending properties of different REBCO coated conductor tapes and Roebel cables atT= 77 K

Otten

Kario

Kling

et al. 2016

Supercond. Sci. Technol.

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show abstract

“…Therefore the mass rests on a sample surface of 50 mm 2 , which is equal to an average pressure of 60 kPa. This pressure level is far too low to cause any measurable effect in current carrying capacity [21,22]. The actual measuring distance from the sample surface is roughly 350 µm, which is equal to the thickness of a varnish layer on the Hall sensor active area used for protection and insulation.…”

Section: Hall Sensor Magnetometermentioning

confidence: 99%

Hall sensor magnetometer for ac characterization of high temperature superconducting tapes

Masti

Lehtonen

Perala

et al. 2005

Meas. Sci. Technol.

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During the last five years, the ac performance of high temperature superconductor (HTS) tapes has been under intense development due to the need of practical applications. In order to measure and understand the current density distributions inside these tapes, several methods have already been developed. However, no system has been able to give the time dependent, spatial distribution of the magnetic flux density at a selected distance above the HTS tape carrying any cyclic current signal. In this paper, such a system operating at a frequency range of 0–400 Hz is presented, and possible error sources are extensively investigated. Post-processing of the measured data is explained in detail and error analysis of several example measurements is given. Measurements with HTS and copper samples are compared in order to demonstrate the usefulness of the system.

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“…This is much higher than comparable stress numbers for both 1G high temperature superconductors (HTS) [4] and low temperature superconductors (LTS) [5]. If we take advantage of YBCO-coated conductors, we can increase current density in the superconducting coils thus reducing their volumes [6].…”

Section: Introductionmentioning

confidence: 95%

Remarkable weakness against cleavage stress for YBCO-coated conductors and its effect on the YBCO coil performance

Yanagisawa

Nakagome

Takematsu

et al. 2011

Physica C: Superconductivity and its Applications

156

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a b s t r a c tCleavage strength for an YBCO-coated conductor at 77 K was investigated with a model experiment. The nominal cleavage strength for an YBCO-coated conductor is extremely low, typically 0.5 MPa. This low nominal cleavage strength is due to stress concentration on a small part of the YBCO-coated conductor in cleavage fracture. Debonding by the cleavage stress occurs at the interface between the buffer layer and the Hastelloy substrate. The nominal cleavage strength for a slit edge of the conductor is 2.5-times lower than that for the original edge of the conductor; cracks and micro-peel existing over the slit edge reduce the cleavage strength for the slit edge. Cleavage stress and peel stress should be avoided in coil winding, as they easily delaminate the YBCO-coated conductor, resulting in substantial degradation of coil performance. These problems are especially important for epoxy impregnated YBCO-coated conductor coils. It appears that effect of cleavage stress and peel stress are mostly negligible for paraffin impregnated YBCO-coated conductor coils or dry wound YBCO-coated conductor coils.

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Axial tensile, transverse compressive and bending strain experiments on Bi(2223)/AgMg single core tapes

Cited by 41 publications

References 4 publications

Bending properties of different REBCO coated conductor tapes and Roebel cables atT= 77 K

Bending properties of different REBCO coated conductor tapes and Roebel cables atT= 77 K

Hall sensor magnetometer for ac characterization of high temperature superconducting tapes

Remarkable weakness against cleavage stress for YBCO-coated conductors and its effect on the YBCO coil performance

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