Effect of GFRP spacer on local deformation of large superconductor in coil pack
- National Inst. for Fusion Science, Gifu (Japan)
Design and construction of the Large Helical Device (LHD) are in progress at the National Institute for Fusion Science (NIFS) in Japan. The LHD has superconducting poloidal and helical coils, and many efforts have been undertaken to develop these large superconductors. When designing a large superconducting magnet, the mechanical behavior of the wound structure becomes a very important factor since the apparent rigidity affects the design of a coil support structure and the superconducting coil needs to endure the large electro-magnetic force it creates. Also, non-linear mechanical behavior should yield the instability of the magnet. In this paper, local deformation in a large conductor caused by GFRP spacers and epoxy adhesives was investigated after compressive rigidity testing. The epoxy adhesive used for attaching the GFRP spacers to the superconductor changed shape from an almost square sheet into a lens-like sheet during deformation, and a dent appeared on the surface of the superconductor. Three-dimensional FEM analysis showed that a compressive stress in the vertical direction of the loading axis existed in the adhesive plane. This stress component makes the adhesive lens-like and it results in the dent created during the compressive testing. This local deformation should yield a part of the permanent deformation observed after the compressive load cycle at 4.2 K.
- OSTI ID:
- 32107
- Report Number(s):
- CONF-930926-; ISSN 0018-9464; TRN: IM9517%%402
- Journal Information:
- IEEE Transactions on Magnetics, Vol. 30, Issue 4Pt2; Conference: 13. international conference on magnet technology, Victoria (Canada), 20-24 Sep 1993; Other Information: PBD: Jul 1994
- Country of Publication:
- United States
- Language:
- English
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