Electromechanical Behavior of Bronze $\hbox{Nb}_{3} \hbox{Sn}$ Strands Under Wide Range Pure-Bending

Chiesa, L.; Allen, N.; King, Joseph; Mallon, Philip; Takayasu, M.

doi:10.1109/tasc.2013.2239353

Cited by 3 publications

(6 citation statements)

References 8 publications

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“…The actual bending strain on the surface of the Nb 3 Sn wire is plotted against the theoretical setting strain of the device in figure 3 [18]. The solid curve represents the corrected bending strain of the sample and appears to closely match the dashed ideal strain curve up to a setting value of 1.0%.…”

Section: Pure Bending Strain Correctionmentioning

confidence: 81%

“…To correct for the noncircular deformation experienced at high bending, above 1.0% setting strain, the actual bending strain on the surface of the Nb 3 Sn wire was determined using finite element simulations. The numerical strain results were averaged over a 50 mm (1.97 ) span in the middle of the The applied setting strain of the bending device plotted versus the actual corrected strain on the surface of the Nb 3 Sn wire as determined from numerical simulations [18]. Above 1.0% the corrected strain begins to significantly deviate from the setting strain.…”

Section: Pure Bending Strain Correctionmentioning

confidence: 99%

“…To quantify the improvement of the new sample holders the bending strain difference on the surface of the Nb 3 Sn wire was calculated using equation (1) [18]. The bending strain difference is a quantitative average of the Lorentz load effect on the wire as determined from numerical finite element simulations.…”

Section: Bending Strain Differencementioning

confidence: 99%

“…Figure 3.The applied setting strain of the bending device plotted versus the actual corrected strain on the surface of the Nb 3 Sn wire as determined from numerical simulations[18]. Above 1.0% the corrected strain begins to significantly deviate from the setting strain.…”

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confidence: 99%

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Wide range pure bending strains of Nb₃Sn wires

Allen

Mallon

King

et al. 2014

Supercond. Sci. Technol.

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Pure bending behavior of Nb 3 Sn wire over a wide range of bending has been characterized. A previously developed test device designed to apply variable bending strains to Nb 3 Sn strands using a beam style sample holder was used. Based on finite element and experimental investigations, two sample holder beams were developed to cover pure bending strains up to 1.25% for ITER-type Nb 3 Sn wires. These newly designed beams were optimized to apply consistent and uniform pure bending strains to Nb 3 Sn strands over the entire bending range. Their performance was evaluated by testing two ITER-type Nb 3 Sn wires including one internal tin and one bronze route. The internal tin strands experienced around 55% critical current degradation at 1.25% bending strain while the critical current of the bronze route strands were only reduced by 40%. Upon removal of the bending load, the internal tin wires experienced significant permanent degradation whereas the bronze route wires were completely reversible. These critical current results were evaluated and explained using an existing integrated model accounting for neutral axis shift, current transfer length, filament breakage and uniaxial strain release under pure bending loads.

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Section: Pure Bending Strain Correctionmentioning

confidence: 81%

Section: Pure Bending Strain Correctionmentioning

confidence: 99%

Section: Bending Strain Differencementioning

confidence: 99%

mentioning

confidence: 99%

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Wide range pure bending strains of Nb₃Sn wires

Allen

Mallon

King

et al. 2014

Supercond. Sci. Technol.

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“…Many experiments and modelling works study the performance degradation of a single strand either in uniform bending [3][4][5] or in periodic bending [6][7][8][9][10]. These loading conditions simulate the real situation of a strand embedded in CICC under operating conditions.…”

Section: Introductionmentioning

confidence: 99%

Simulation of transport properties in Nb3Sn strand under bending

Zhao

et al. 2015

Cryogenics

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The effect of axial and transverse loading on the transport properties of ITER Nb₃Sn strands

Nijhuis

Meerdervoort

Krooshoop

et al. 2013

Supercond. Sci. Technol.

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The differences in thermal contraction of the composite materials in a cable in conduit conductor (CICC) for the International Thermonuclear Experimental Reactor (ITER), in combination with electromagnetic charging, cause axial, transverse contact and bending strains in the Nb 3 Sn filaments. These local loads cause distributed strain alterations, reducing the superconducting transport properties. The sensitivity of ITER strands to different strain loads is experimentally explored with dedicated probes. The starting point of the characterization is measurement of the critical current under axial compressive and tensile strain, determining the strain sensitivity and the irreversibility limit corresponding to the initiation of cracks in the Nb 3 Sn filaments for axial strain. The influence of spatial periodic bending and contact load is evaluated by using a wavelength of 5 mm. The strand axial tensile stress-strain characteristic is measured for comparison of the axial stiffness of the strands. Cyclic loading is applied for transverse loads following the evolution of the critical current, n-value and deformation. This involves a component representing a permanent (plastic) change and as well as a factor revealing reversible (elastic) behavior as a function of the applied load.The experimental results enable discrimination in performance reduction per specific load type and per strand type, which is in general different for each manufacturer involved. Metallographic filament fracture studies are compared to electromagnetic and mechanical load test results. A detailed multifilament strand model is applied to analyze the quantitative impact of strain sensitivity, intrastrand resistances and filament crack density on the performance reduction of strands and full-size ITER CICCs. Although a full-size conductor test is used for qualification of a strand manufacturer, the results presented here are part of the ITER strand verification program. In this paper, we present an overview of the results and comparisons.

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Electromechanical Behavior of Bronze $\hbox{Nb}_{3} \hbox{Sn}$ Strands Under Wide Range Pure-Bending

Cited by 3 publications

References 8 publications

Wide range pure bending strains of Nb₃Sn wires

Wide range pure bending strains of Nb₃Sn wires

Simulation of transport properties in Nb3Sn strand under bending

The effect of axial and transverse loading on the transport properties of ITER Nb₃Sn strands

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Electromechanical Behavior of Bronze $\hbox{Nb}_{3} \hbox{Sn}$ Strands Under Wide Range Pure-Bending

Cited by 3 publications

References 8 publications

Wide range pure bending strains of Nb3Sn wires

Wide range pure bending strains of Nb3Sn wires

Simulation of transport properties in Nb3Sn strand under bending

The effect of axial and transverse loading on the transport properties of ITER Nb3Sn strands

Contact Info

Product

Resources

About

Wide range pure bending strains of Nb₃Sn wires

Wide range pure bending strains of Nb₃Sn wires

The effect of axial and transverse loading on the transport properties of ITER Nb₃Sn strands