Direct measurement of Nb$_3$Sn filament loading strain and stress in accelerator magnet coil segments
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In this article, a load frame that enables rotation of the sample load axis with respect to the neutron scattering geometry was installed in the Stress-Spec beamline at the Heinz Maier-Leibnitz FRM II neutron source.Abstract:
We have directly measured, for the first time, the Nb3Sn and Cu loading strains and stresses in 11 T dipole coil segments upon compressive loading using neutron diffraction. For this purpose a load frame that enables rotation of the sample load axis with respect to the neutron scattering geometry was installed in the Stress-Spec beamline at the Heinz Maier-Leibnitz FRM II neutron source. The neutron diffraction data suggests that the magnet coil wound of Rutherford type cables can be considered as a fibre reinforced composite material. In the axial load direction the load is mainly carried by the Nb3Sn filaments and the composite stiffness can be estimated by the rule of mixtures assuming iso-strain conditions in all composite constituents. Under transverse compression the fully annealed Cu provides an isotropic pressure around the Nb3Sn filaments. The transverse load stresses in the Cu and Nb3Sn are similar, indicating iso-stress behaviour of the coil constituents under transverse compression. The broadening of the Nb3Sn diffraction peaks above critical stress values indicates reversible and irreversible Nb3Sn loading stress effects.read more
Citations
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Effect of Epoxy Volume Fraction on the Stiffness of Nb 3 Sn Rutherford Cable Stacks
Felix Wolf,Friedrich Lackner,Michael Hofmann,Christian Scheuerlein,Daniel Schoerling,Davide Tommasini +5 more
TL;DR: In this paper, the authors measured the stiffness of Nb3Sn Rutherford cable stacks with different epoxy volume fraction and found that the cable stack stiffness is strongly dependent on the load direction.
Journal ArticleDOI
Metallographic analysis of 11 T dipole coils for High Luminosity-Large Hadron Collider (HL-LHC)
Shreyas Balachandran,Jonathan Cooper,Orion B Van Oss,Peter J. Lee,Luca Bottura,Arnaud Devred,Frederic Savary,Christian Scheuerlein,Felix Wolf +8 more
TL;DR: In this paper, the authors present evidence of cracking of the brittle Nb3Sn filaments in a prototype dipole that resulted in degraded magnet performance, which can be attributed to an issue with the collaring process that is required in the assembly of dipole accelerator magnets.
Journal ArticleDOI
Effect of the fabrication route on the phase and volume changes during the reaction heat treatment of Nb 3 Sn superconducting wires
Christian Scheuerlein,Jérôme Andrieux,Matthias Michels,Friedrich Lackner,C. Meyer,Rodica Chiriac,François Toche,M Hagner,M. Di Michiel +8 more
TL;DR: In this article, the phase and microstructure changes during the processing of Restacked Rod Process (RRP), powder-in-tube (PIT) and Internal Tin (IT) Nb3Sn wires were investigated.
Journal ArticleDOI
Effect of Applied Compressive Stress and Impregnation Material on Internal Strain and Stress State in Nb 3 Sn Rutherford Cable Stacks
Felix Wolf,Christian Scheuerlein,Marcus Lorentzon,Balduin Katzer,Michael Hofmann,Weimin Gan,Friedrich Lackner,Daniel Schoerling,Davide Tommasini,Frederic Savary,Luca Bottura +10 more
TL;DR: In this paper, the elastic strain evolution of Nb3Sn Rutherford type cables with different impregnation and coil blocks extracted from an 11 T dipole short model coil were investigated.
Journal ArticleDOI
Grain boundary deformation in uniaxial strained Nb3Sn
TL;DR: In this article, a three-dimensional stress map of grains and grain boundaries in uniaxial strained Nb3Sn composite is generated using a scale-coupled model generated by the polycrystalline finite element method and based on the linear elastic theory of closely packed fiber-reinforced composites.
References
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Journal ArticleDOI
Berechnung der elastischen Konstanten des Vielkristalls aus den Konstanten des Einkristalls
TL;DR: In this article, anwendungsmoglichkeiten der Methode werden besprochen, in which experimentelle Vergleichswerte weichen von den berechneten etwas ab, was beweist, das die Experimente nicht den von der Theorie geforderten idealen Bedingungen genugt haben.
Book
Introduction to the Characterization of Residual Stress by Neutron Diffraction
TL;DR: In this article, the authors discuss the development of stress measurement by diffraction and the characteristics of Neutron Strain Measurement, including extinction, texture, and multiple scattering.
Journal ArticleDOI
Strain scaling law for flux pinning in practical superconductors. Part 1: Basic relationship and application to Nb3Sn conductors
TL;DR: In this article, the authors present the basic uniaxial-strain scaling relationship and focus on its application to Nb3Sn conductors, and propose a general scaling relation which unifies the usual temperature scaling relation with this strain-scaling relation.
Journal ArticleDOI
Advanced Accelerator Magnets for Upgrading the LHC
TL;DR: In this article, the authors reviewed the last ten year of Nb3Sn accelerator magnet R&D and compared it to the needs of the upgrades and critically assessed the results of the Nb 3Sn and HTS technology and the planned R&DD programs also based on the inputs of first year of LHC operation.
Journal ArticleDOI
Effect of transverse compressive stress on the critical current and upper critical field of Nb3Sn
TL;DR: In this article, a large reversible degradation of the critical current of multifilamentary Nb3Sn superconductors was observed when uniaxial compressive stress is applied transverse to the conductor axis at 4 K.