Mechanical testing of collared coil mock-ups based on the 11 T dipole cross section

Thursday 31 Mar 2022, 10:30 → 12:00 Europe/Zurich

ZOOM

Alessandro Bertarelli (CERN), Friedrich Lackner (CERN)

Abstract:

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In the framework of the HL-LHC project, several mock-up tests were carried out to study stresses and strains in the cross-section of the Nb3Sn superconducting coil.

This is particularly relevant for the 11T dipole magnet, in which the collaring technology was chosen to preload the coil cross-section at room temperature. Recent studies have underlined that the loading sequence can result in local conductor degradation, adversely affecting the coil critical current.  In this context, an extensive campaign was jointly undertaken by TE-MSC and EN-MME to investigate the mechanical effects of assembling conditions and of manufacturing tolerances on the deformation under compressive loads of the 11 T collared structure. The campaign was based on a series of full-scale collared coil mock-ups. A comprehensive test methodology was established, entailing stringent QC on the mock-up components. The compressive tests were performed in controlled conditions, monitoring force, displacement, strains and stresses, and were benchmarked against 3-D nonlinear finite element models, in which geometrical imperfections were also integrated.

The seminar will summarize the main results obtained, highlighting the most interesting findings, and the challenges met. Possibilities offered by this methodology in future magnet developments will also be discussed.

11TMockup_MSC_Seminar_Mar_22.pptx