Experimental and Numerical Analysis of High-Temperature Superconducting Tapes Modified by Composite Thermal Stabilization Subjected to Thermomechanical Loading

Abstract

The strain behavior of SiC/Stycast 2850 FT composites under thermomechanical loading using a finite element analysis (FEA) was studied. These composites can serve as thermal stabilizers of high-temperature superconducting (HTS) tapes during limitation event in resistive superconducting fault current limiter (R-SCFCL) applications. For this purpose, the thermomechanical properties of four composite systems with different filler content were studied experimentally. The FEA was calculated using an ANSYS software and it delivered useful information about the strain distribution in the composite coating, as well as in particular layers of the modified HTS tapes. The tapes were subjected to bending over a 25 cm core, cooled in a liquid nitrogen (LN2) bath, and finally, quenched from this temperature to various temperatures up to 150 °C for a very short time, simulating real limitation conditions. The outputs from simulations were also correlated with the experiments. The most promising of all investigated systems was SB11-SiC20 composite in form of 100 µm thick coating, withstanding a temperature change from LN2 up to 120 °C.

Mechanics of dielectric polyamide/SiO2 nanocomposite coatings for cryogenic service in superconductor systems

“…However, the imidization reaction and thermal annealing processes require temperatures far greater than 200 C. Such high processing temperatures increase the vulnerability of HTS tapes to delamination caused by excessive thermal stresses during processing. 6,35,37 Therefore, achieving the low temperature curing of a polyamic acid solution to generate aromatic polyamide enamels without high-temperature processing became a focal point in this study. To address the aforementioned challenge, Dupont Pyre-M.L.…”

“…54 Following the coating of a substrate with the precursor solution, solvent evaporation and thermal curing steps must yield a solid dielectric enamel without exceeding the 150 C temperature threshold where delamination of 2G HTS tapes can occur. 6,35,37 The Stöber process is regarded as the simplest and most effective route to prepare monodisperse silica nanospheres inside of a polymer solution. 41,55 The process, which has been widely used to develop catalysts, pigments, pharmaceuticals, and coatings for electronics, can be easily modified to suit the industrial manufacturing of PA/SiO 2 dielectric coatings for superconductors.…”

“…To accomplish this, a PA/SiO 2 nanocomposite precursor solution must be prepared such that it remains homogeneously dispersed in the fluid medium during processing and avoids macroscopic gelation that would hinder the repeatable sample preparation 54 . Following the coating of a substrate with the precursor solution, solvent evaporation and thermal curing steps must yield a solid dielectric enamel without exceeding the 150°C temperature threshold where delamination of 2G HTS tapes can occur 6,35,37 . The Stöber process is regarded as the simplest and most effective route to prepare monodisperse silica nanospheres inside of a polymer solution 41,55 .…”