A Three-Dimensional Discrete Element Model for an NbTi/Cu Composite Strand

The mechanical behaviors of a composite superconducting strand, which is composed of a variety of materials with different mechanical properties, are difficult to be accurately predicted using traditional mechanical methods due to the complex modeling process and difficulties in dealing with the interactions among different materials as well as material failure. In this paper, a three-dimensional equivalent discrete element model of an NbTi/Cu composite strand is established by twisting process first, and its mechanical response under external load is successfully achieved by introducing different material constitutive relations into contact models discriminatively and taking the filament fracture into consideration. Thismodel can reduce the modeling process largely and acquire more accurate results, which can also provide a new thinking in predicting themechanical performance of other superconducting strand or composite material.