Finite-element structural analysis of the 10 m long dipole prototype magnet for the LHC

In the framework of the R&D program for the LHC (Large Hadron Collider) superconducting magnets, a series of dipole prototypes, manufactured by European firms, will be placed in a test cell of the LHC machine to be tested in the second part of 1992. The design of the cross-section of the full length dipole prototype is a natural evolution from the solutions adopted in the CERN models and prototypes developed and built so far. A detailed finite-element stress and strain analysis was carried out and the results were used to complete the design of the prototype. The optimization of the design was done by studying the magnet behavior at room temperature, and at 1.8 K in both energized and nonenergized conditions. The Lorentz body forces distribution, corresponding to a 10-tesla central field, was computed from a magnetic field analysis by means of the same finite-element package used in the stress-strain analysis. The authors report on the main results obtained, and illustrate the guidelines which were followed in optimizing the design of the cross section