Investigation of Adopting Shrink-Fit Multilayered Aluminum Shell in High-Field Common-Coil Accelerator Dipole Magnet

This paper presents the shrink-fit multilayered aluminum shell (SMAS) used for withstanding large Lorentz force in a 20-T shell-based common-coil accelerator dipole magnet. Finite element analysis (FEA) is carried out to optimize the required shell thickness when a single layer aluminum shell is used to support the 20-T dipole magnet. Also, FEA is carried out to study the performance of a three-layer SMAS used in the same dipole magnet. The analyzed results indicate that the three-layer SMAS with thickness of 75 mm can help us to reduce the peak shell stress significantly compared to a 75-mm-thick single layer aluminum shell when they provide the same preload to the coils. Some preliminary experiments have been carried out which prove that the initial stress distribution in the SMAS can be well controlled after the assembly. Hopefully, the outer diameter of the twin-aperture 20-T common-coil dipole magnet can be restricted to 900 mm if we use a three-layer SMAS as the support structure.