Geometrical modeling and mechanical behavior analysis of Nb3Sn Rutherford cable

Abstract

The energy upgrade of the Large Hadron Collider and Future Circular Collider propose new requirement that the magnetic field of accelerate magnets is up to 16 T. Nb3Sn Rutherford cables are used in magnet design for such high level magnetic field. Rutherford cables must undergo complex stress conditions owing to the extreme magnetic environment and complicated cabling process which often leads to mechanical instability. In this study, a three-dimensional model is established and analyzed to better understand the mechanical behavior of Rutherford cables subjected to different loading conditions during the cabling process. A rapid approach to construct the geometry of a Rutherford cable is first presented, followed by an analysis of its mechanical behavior under axial tension, cyclic tension and transverse compression conditions. Instability behaviors, such as “pop-out” and “cross-over”, are investigated. The results show that the friction coefficient, laying angle and core play important roles in the cable mechanical performance. For better mechanical stability of the strands in Rutherford cables, it is recommended to select a higher friction value among the strands and a laying angle between 74° and 78° for non-cored cable, whereas a larger laying angle is suggested for copper-cored cable.