Structural modeling of HTS tapes and cables

Allen, N.; Chiesa, L.; Takayasu, M.

doi:10.1016/j.cryogenics.2016.02.002

Cited by 61 publications

(18 citation statements)

References 27 publications

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“…Given the strain dependence of I c , the presented approach allows to determine the expected I c of the REBCO tape after bending [45][46][47][48]. Considering the I c dependence on both strain and magnetic field, one can determine the expected cable and magnet performance in order to assess if the fabrication process has introduced any conductor degradation [49].…”

Section: Discussionmentioning

confidence: 99%

Strain Distribution in REBCO-Coated Conductors Bent With the Constant-Perimeter Geometry

Wang

Arbelaez

Caspi

et al. 2017

IEEE Trans. Appl. Supercond.

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Abstract-Cable and magnet applications require bending REBa2Cu3O 7−δ (REBCO, RE = Rare Earth) tapes around a former to carry high current or generate specific magnetic fields. With a high aspect ratio, REBCO tapes favor the bending along their broad surfaces (easy way) than their thin edges (hard way). The easy-way bending forms can be effectively determined by the constant-perimeter method that was developed in the 1970s to fabricate accelerator magnets with flat thin conductors. The method, however, does not consider the strain distribution in the REBCO layer that can result from bending. Therefore, the REBCO layer can be over-strained and damaged even if it is bent in an easy way as determined by the constant-perimeter method.To address this issue, we developed a numerical approach to determine the strain in the REBCO layer using the local curvatures of the tape neutral plane. Two orthogonal strain components are determined: the axial component along the tape length and the transverse component along the tape width. These two components can be used to determine the conductor critical current after bending. The approach is demonstrated with four examples relevant for applications: a helical form for cables, forms for canted cos θ dipole and quadrupole magnets, and a form for the coil end design. The approach allows to optimize the design of REBCO cables and magnets based on the constantperimeter geometry and to reduce the strain-induced critical current degradation.

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Section: Discussionmentioning

confidence: 99%

Strain Distribution in REBCO-Coated Conductors Bent With the Constant-Perimeter Geometry

Wang

Arbelaez

Caspi

et al. 2017

IEEE Trans. Appl. Supercond.

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“…The tape was modeled using SOLSH190, an 8-node solid shell element which prescribes the tape to be a uniform volume with specified material properties of each individual layer [15]. A thin layer of solder was modelled between the tape and the U-spring, and bonded contact conditions were used.…”

Section: B Residual Thermal Strain In the Rebco Layer: Fea Studymentioning

confidence: 99%

“…For the Uspring, thermal material proprieties of pure copper were assigned. Mechanical and thermal properties of the materials can be found in [15]- [17]. Based on the FEA results, a residual thermal strain of -0.05% was estimated for the REBCO layer prior to testing at 77 K (Fig.…”

Section: B Residual Thermal Strain In the Rebco Layer: Fea Studymentioning

confidence: 99%

Measurements of the Strain Dependence of Critical Current of Commercial REBCO Tapes at 15 T Between 4.2 and 40 K for High Field Magnets

Pierro

Delgado

Chiesa

et al. 2019

IEEE Trans. Appl. Supercond.

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Interest for high magnetic fields (>16 T) for applications in high energy physics (HEP) and fusion machines, requires the development of high current cables capable to withstand the large forces, mechanical and electromagnetic, experienced during manufacturing and operations. The critical current (Ic) of REBCO tapes depends on strain, magnetic fields and operational temperatures. Understanding how these parameters affect the Ic of the conductor will be critical to develop robust high-current REBCO cables. However, there are limited reports on the strain dependence of Ic, in particular at high fields and elevated temperatures relevant for future high-field compact fusion reactor magnets.We present Ic of commercial REBCO tapes measured as a function of compressive and tensile strain (between -0.6% and +0.65%) at high magnetic fields (12 T and 15 T) and different temperatures (within 4.2 K-40 K). Results at 4.2 K and 20 K showed less than 5% reduction in the normalized Ic at high strain, while a stronger strain dependence was observed at 40 K. Samples tested at 12 T and 4.2 K showed similar strain dependence as 15 T and 4.2 K. In all tested conditions, the tape experienced reversible Ic reduction in both tension and compression. Finite element analysis was used to predict the residual thermal strain accumulated in the REBCO layer prior of testing to account for the effect of the cooldown. A method was also developed to account for the current sharing observed between the sample and the sample holder during the ramp of the current. Our results provide useful input for the development of high-field fusion and HEP magnets using REBCO conductors.Index Terms-High-field fusion magnets, high-temperature superconductors, strain measurement, superconducting cables, yttrium barium copper oxide. R This is the author's version of an article that has been published in this journal. Changes were made to this version by the publisher prior to publication.The final version of record is available at http://dx.

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“…HTS tapes were modeled as a uniform volume using SOLSH190 structural solid-shell elements using a novel technique developed in [8]. Each tape was modelled with a uniform thickness along the width, neglecting the thickness variation in the copper layers typically observed in real tapes.…”

Section: Element Type and Mesh Densitymentioning

confidence: 99%

“…Each tape was modelled with a uniform thickness along the width, neglecting the thickness variation in the copper layers typically observed in real tapes. Details of the modeling of the multi-layer tape as uniform volume are listed in [8]- [9]. The support structure was meshed using SOLID185 homogeneous structural solid elements.…”

Section: Element Type and Mesh Densitymentioning

confidence: 99%

Finite element investigation of the mechanical behaviour of a Twisted Stacked-Tape Cable exposed to large Lorentz loads

Pierro

Zhao

Chiesa

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. The mechanical response of Twisted Stacked-Tape Cables (TSTC) experiencing large Lorentz loads generated during its operation in high-current, high-field magnets was investigated using finite element analysis. Two conductor configurations were investigated: a stack of 40 REBCO tapes inside a solid cylindrical copper rod (former) and a solder filled copper tube. Several simulations were conducted to highlight the effect of different parameters in the cable and the differences between the two configurations. A parametric study on the geometrical parameters of the solder filled tube configuration was performed. It was found that increasing the ratio between the thickness of the copper tube and the amount of solder in the cross section lowers the maximum stress experienced by the stack of tapes. Another simulation explored the effect of using different width tapes in the stack and it was found that, for a given Lorentz load, a wider tape reduces the maximum stress experienced by the stack. In certain applications, the cable requires the addition of material for structural support or stability reasons therefore a simulation was performed to understand the effect of copper surroundings. It was found that surrounding the cable with copper as well as using a thick copper tube lowers the stress experienced by the stack and makes the behaviour of the copper core and the solder filled tube configurations almost identical. Finally, the critical current performance of the TSTC conductors as a function of Lorentz load was estimated. A minimal degradation below 2% was predicted for the copper core configuration up to 1000 kN/m and up to 600 kN/m for the solder filled tube configuration.

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Structural modeling of HTS tapes and cables

Cited by 61 publications

References 27 publications

Strain Distribution in REBCO-Coated Conductors Bent With the Constant-Perimeter Geometry

Strain Distribution in REBCO-Coated Conductors Bent With the Constant-Perimeter Geometry

Measurements of the Strain Dependence of Critical Current of Commercial REBCO Tapes at 15 T Between 4.2 and 40 K for High Field Magnets

Finite element investigation of the mechanical behaviour of a Twisted Stacked-Tape Cable exposed to large Lorentz loads

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