Shear test of glass reinforced composite materials at 4.2 K

Finite element analysis of the 4-T, 12.5-m long, 6-m-bore diameter superconducting solenoid for the CMS experiment at LHC shows that the insulation system is subjected mainly to shear forces during magnet operation at 4.5 K. This paper describes the development of a test procedure to evaluate shear properties of the glass reinforced composite material at 4.2 K. The calculation supporting the new specimen shape and the relation between coil and specimen Finite Element Analysis (FEA) are presented. As an application, this-test procedure is used to compare three different surface treatments of the conductor: solvent cleaning, sand blasting and anodic oxidation. Results from these tests are reported. Values up to 110 MPa at 4.2 K have been obtained for the CMS foreseen insulation material, the conductor being treated by anodic oxidation.