Nb3Sn magnets with a nominal operation field of 15-16 T are being considered for the LHC energy upgrade (HE-LHC) and a post-LHC Future Circular Collider (FCC). To demonstrate the feasibility of 15 T accelerator quality dipole magnets, the US Magnet Development Program (MDP) is developing a single-aperture 15 T Nb3Sn dipole demonstrator based on a 4-layer graded cos-theta coil with 60 mm aperture and cold iron yoke. The main design challenges for 15 T accelerator magnets include large Lorentz forces at this field level. To counteract them, an innovative mechanical structure based on a vertically split iron yoke, locked by large aluminum IC-clamps and supported by a thick stainless steel skin, has been developed at Fermilab. To study the performance of the structure a parametric multi-physics FEA model has been set-up by FEAC. This paper describes the numerical model as well as the results of a sensitivity analysis of the effect of geometrical tolerances and assembly parameters.
*Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy