Effects of Transverse Compressive Stress on CORC Cables Under Various Mechanical Support Conditions

Abstract

CORC ReBCO cables are promising conductors for the next generation of high-performance cables for high-field accelerator magnets. However, because significant mechanical stress is inevitable in high field magnet applications, the deformation and damage of these cables under large stresses should be explored. Focusing on high field accelerator dipole inserts for a moment, various mechanical configurations for the winding are under consideration, which may affect cable performance. Therefore, the relationship between mechanical support conditions and the mechanical performance of CORC ReBCO cable under transverse compressive stress should be explored. In this study, the effects of transverse pressure on CORC cables with either side support during pressure application, or epoxy impregnation, or both, were investigated. Several segments of a particular CORC cable were used in four different mechanical configurations; (i) as received, (ii) unpotted but with side support, (iii) potted without side support, and (iv) potted and with side support. A material Testing System (MTS model 43) was utilized to compress our samples up to 30 kN in four different supporting conditions as listed above. Samples were autopsied using optical as well as scanning electron microscopy after the completion of the mechanical tests. As a result, we found that the support conditions enhance the mechanical performance of the CORC cable by extending the elastic-plastic transition load to a larger stress level, and we also observe cleavage cracks after the completion of the compressive stress test.