Effect of Periodic Cyclic Deformation on the Voltage Current Transition of&amp;lt;tex&amp;gt;$hboxNb_3hboxSn$&amp;lt;/tex&amp;gt;Strands Tested in the Novel ‘TARSIS’ Setup

Nijhuis, A.; Ilyin, Y.; Wessel, Wilhelm A.J.; Abbas, Wouter; Kate, H. Ten

doi:10.1109/tasc.2004.830654

Cited by 22 publications

(19 citation statements)

References 9 publications

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“…The plastic deformation of the copper during bending is included in the deflection but not considered as a separate mechanism in the analysis on bending. The effects starts to become relevant for bending wavelengths of less than 5 mm [57].…”

Section: The Periodic Bending Probementioning

confidence: 98%

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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Section: The Periodic Bending Probementioning

confidence: 98%

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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“…Moreover, the strain due to thermal treatment is only part of the total strain field since the helicoidal geometry of the wires inside the cable -and of the filaments inside the wirecauses an additional strain [6]. Furthermore, when the coil is energized, electromagnetic forces act as bending loads on the wires, which behave like continuous beams supported by the contacting wires in their neighbourhood, so that a bending strain is added to the existing strain field [7][8][9][10].…”

Section: A Real Casementioning

confidence: 99%

“…3), such that for each given, uniform, and monotonic increment ΔT of temperature T and for each given external kinematical load increment, they satisfy Eqs. (1)- (7) and:…”

Section: Problem P1mentioning

confidence: 99%

Generalized self‐consistent like method for mechanical degradation of fibrous composites

2011

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This paper deals with homogenization of heterogeneous, fibre-reinforced material. One of the main points of the work consists in taking into account the breakage of the fibres, to compute the effective behaviour of the damaged composite. Furthermore, the possible yielding of the matrix material is considered. The problem is solved for the coupled thermo-mechanical field, that is all material characteristics can be temperature dependent and thermal loads can be simulated. The method is based on a self consistent type scheme, suitably extended for the case at hand. The effective behaviour is obtained by considering isotropic elastic-brittle cylindrical inclusions surrounded by a shell of elasto-plastic matrix material immersed in an infinite medium endowed with the effective properties. Usually in the framework of the self consistent scheme, the homogenised material behaviour is obtained with a symbolic approach. On the contrary, in this work the solution is found in a non-classical way, as we use the finite element method to find the solution of the thermo-mechanical problem as a function of the effective material characteristics. This paper deals with homogenization of heterogeneous, fibre-reinforced material. One of the main points of the work consists in taking into account the breakage of the fibres, to compute the effective behaviour of the damaged composite. Furthermore, the possible yielding of the matrix material is considered. The problem is solved for the coupled thermomechanical field, that is all material characteristics can be temperature dependent and thermal loads can be simulated. The method is based on a self consistent type scheme, suitably extended for the case at hand. On the contrary, in this work the solution is found in a non-classical way, as we use the finite element method to find the solution of the thermomechanical problem as a function of the effective material characteristics

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“…But for the Nb3Sn CICC I did not see much of a deviation from an exponent. For the individual strands that were bent by a regular array of pins [11] the UT group reported the shapes of the transitions, see Fig. 14 below. Indeed, there is some distortion, but not very dramatic, like in our case To or N varies almost by a factor of 3 on the same curve.…”

Section: Fig 12 Assessment Of Tcs In Tfas1 and Tfas2 Testsmentioning

confidence: 99%

SULTAN measurement and qualification: ITER-US-LLNL-NMARTOVETSKY- 092008

Martovetsky¹

2006

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Executive summaryMeasuring the characteristics of full scale ITER CICC at SULTAN is the critical qualification test. If volt-ampere characteristic (VAC) or volt-temperature characteristic (VTC) are distorted, the criterion of 10 uV/m may not be a valid criterion to judge the conductor performance. Only measurements with a clear absence or low signals from the current distribution should be considered as quantitatively representative, although in some obvious circumstances one can judge if a conductor will meet or fail ITER requirements. SULTAN full scale ITER CICC testing should be done with all measures taken to ensure uniform current redistribution. A full removal of Cr plating in the joint area and complete solder filling of the joints (with provision of the central channel for helium flow) should be mandatory for DC qualification samples for ITER. Also, T and I should be increased slowly that an equilibrium could be established for accurate measurement of Tcs, Ic and N. It is also desirable to go up in down in current and/or temperature (within stable range) to make sure that the equilibrium is reached.

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Effect of Periodic Cyclic Deformation on the Voltage Current Transition of<tex>$hboxNb_3hboxSn$</tex>Strands Tested in the Novel ‘TARSIS’ Setup

Cited by 22 publications

References 9 publications

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

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

Generalized self‐consistent like method for mechanical degradation of fibrous composites

SULTAN measurement and qualification: ITER-US-LLNL-NMARTOVETSKY- 092008

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Effect of Periodic Cyclic Deformation on the Voltage Current Transition of&lt;tex&gt;$hboxNb_3hboxSn$&lt;/tex&gt;Strands Tested in the Novel ‘TARSIS’ Setup

Cited by 22 publications

References 9 publications

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

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

Generalized self‐consistent like method for mechanical degradation of fibrous composites

SULTAN measurement and qualification: ITER-US-LLNL-NMARTOVETSKY- 092008

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Product

Resources

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Effect of Periodic Cyclic Deformation on the Voltage Current Transition of<tex>$hboxNb_3hboxSn$</tex>Strands Tested in the Novel ‘TARSIS’ Setup

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

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