Numerical model for transverse current transport in multi-filament twisting strands under uniform axial strain

• Published in: Cryogenics (Guildford) Vol. 129; p. 103617
• Main Authors: Hong, Yang, Li, Yingxu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2023
• Subjects: Contact resistance; Electro-mechanical coupling; Finite element analysis; Multi-filament twisting strand; Transverse current flow; Contact resistance; Electro-mechanical coupling; Multi-filament twisting strand; Finite element analysis; Transverse current flow
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/j.cryogenics.2022.103617

•The contact resistance is sensitive to the n value.•Filaments improve the capacity of transverse transport.•Strand’s capability to carry transverse current is declined under strain. This paper establishes a three-dimensional finite element model for multi-filament twisting strands. The model studies the changes in its transverse transport properties by applying uniform axial loads. The electro-mechanical coupling relation of superconducting filaments is established by the scaling law and n-power relation. When the average strain of the filaments is between 0.1% and 0.2%, the equivalent conductivity of filaments almost decreases linearly by 67.7% with respect to that for zero-strain. Meanwhile, the contact resistance Rc increases quadratically with the strain, the value of Rc=3.9×10-15Ωm2 is calculated at strain 0.2% and n=6, and reaches the same order of magnitude as the previous work. As n increases from 6 to 10, the contact resistance increases sharply by 104 order of magnitude in unit of Ω·m2. It is indicated that the contact resistance is sensitive to the n value. By gradually increasing the number of filaments in a strand model, the average potential difference decreases in a nearly linear manner, and the minimum value of 9.9×10-11V is found for the strand of 36 filaments at 0.2% strain. It suggests that filaments improve the capacity of transverse transport. Besides, the average transverse current density of the strand is suppressed by the strain, its value decreasing from 800A/m2 at zero strain to 570A/m2 at 0.2% strain. It is shown that its capability to carry transverse current is declined under strain.