Study of thermo-elasto-plastic behaviors of twisted multi-filamentary superconducting strands and structures using incremental Mori-Tanaka method

An efficient estimation of the thermo-elasto-plastic behaviors of twisted multi-filamentary superconducting strands and structures is crucial for the superconducting conductor design and application. In this paper, an incremental Mori-Tanaka method is adopted to study the thermo-elasto-plastic behaviors of twisted multifilamentary superconducting strands and structures. The mechanical behavior of copper matrix is described by nonlinear kinematic hardening plasticity and numerically realized using a midpoint algorithm. The effect of the twisted filament is considered by rotational transformation along the helical filament. The incremental MoriTanaka method is integrated into finite element simulation using the UMAT subroutine in ABAQUS. The applicability of the developed model is validated by comparing with direct numerical simulations. Then, the comparison with experimental results shows that the incremental MT method can characterize the experimental results effectively. The macroscopic mechanical behaviors of twisted multi-filamentary superconducting strands with different twist pitches are studied, and the thermal loading is considered. Finally, the idealized superconducting structure analysis is conducted to illustrate the application of the developed incremental MT method on a larger scale.