科研之友
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摘要
At present, conventional low-temperature superconductors such as Nb3Sn strands have been extensively applied in high-energy and nuclear physics, as well as in magnetic resonance imaging systems. In this paper, a 3D finite element model considering sophisticated structure of superconducting filament bundles and metal matrix elements is built to deal with the electromagnetic behaviors of a Nb3Sn strand exposed to tension and bending loads. The mechanical constitutive relations of filament bundles and metal matrix are described with elastic and elasto-plastic axial stress-strain curve, respectively. The voltage-current characteristic of the metal matrix elements is determined with the Ohmic law, and that of the superconducting filaments follows the n power relation. The stress-strain state is simulated and then implemented in the electromagnetic model, through the scaling law of ITER Nb3Sn strand. We find that the plasticity of copper and the twist filaments cause the enhanced inhomogeneous strain profile in a strand composite, compared to the strain profile in a strand with untwisted filaments. We also discuss the current/field profile, critical current degradation, and AC loss in the strand composite under the tension and bending loads.
- 出版日期2015-9
- 单位兰州大学
