Updates on the Mechanical Design of FalconD, a Nb$_3$Sn Cos$\Theta$ Short Model Dipole for FCC-hh

As part of the research project called FCC-hh led by CERN, which aims to study the possibility of building a new 100 TeV center of mass energy particle collider along an 80-100 km circumference tunnel, there are many collaborations underway to test different designs for the main bending dipole of the collider. One of these collaborations involves INFN, the Italian Institute of Nuclear Physics, which has been working on the cos $\theta$design until 2019 as part of the European EuroCirCol project. This study consisted of a conceptual design of a 16 T, double-aperture, four-layer dipole made of Nb$_{3}$Sn. Considering the challenge that such a cutting-edge magnet represents, this conceptual design resulted in a 5-year agreement between INFN and CERN in order to study and build a 1.5 m long, single aperture, cos $\theta$, Nb$_{3}$Sn dipole with a target magnetic field of 12 T. This project is called the Future Accelerator post-LHC Cos $\theta$Optimized Nb$_{3}$Sn Dipole (or FalconD for short). In this paper we present the mechanical analysis of this project after some major cross-sectional upgrades that have impacted the design by easing the assembly phase. One of the most challenging aspects of this design is its mechanical structure that must handle the intense magnetic forces generated by such a high magnetic field. The mechanical structure is based on the “bladder & key” (B&K;) concept and it has never been adopted before in a cos$\theta$dipole, so it needs to be validated. This contribution presents the 2D FEM of the FalconD, showing the mechanical behavior of the magnet during each construction step.