Plastic Deformation Simulation of REBCO Tapes Using Particle Methods

Abstract

Ultra-high field superconducting magnets are facing a mechanical degradation problem. On 2017, a world-record high DC magnetic field of 45.5 T was generated by insert no-insulation (NI) Rare-Earth Barium Copper Oxide (REBCO) pancake coils (14.4 T), called "LBC3", and an outsert resistive magnet (31.1 T). Although the experiment showed a high potential of the NI REBCO magnets for ultra-high field generation, the insert NI REBCO pancake coils and the REBCO tapes were plastically deformed. The critical current properties of damaged REBCO tapes were degraded although the Hastelloy substrate of REBCO tapes is stiff and it has a high yield point of approximately 1 GPa. However, the mechanisms of the damaging REBCO tapes are not clarified. Therefore, it is necessary to clarify the mechanical phenomenon of REBCO tapes.In this paper, we model a REBCO tape with a smoothed particle hydrodynamics (SPH) method, which can represent plastic deformation. The SPH simulation is coupled with electromagnetic analysis with a partial element equivalent circuit (PEEC) model which we have previously developed. In the simulation, an external field, which linearly increases to 5 T and then decreases to 0 T, is applied to a short-length REBCO tape. The simulation results show that the REBCO tape largely deforms during the external field excitation and deexcitation.

Inductive Voltage of Insert HTS Coils Due to Coil Deformation for Ultra-High Magnetic Field Generation

“…It has long been known that a large electromagnetic force causes the insert magnet to expand. Recently, the deformation of insert REBCO pancake coils for ultra-high magnetic field generation has been reported [18], [26], [27]. The insert REBCO coils deform greatly due to high current densities in high magnetic fields generated by the outsert magnets.…”

Investigation into accuracy of turn-to-turn contact resistance measurement in low-frequency AC method by 3D numerical simulation

“…As a simulation model for comparison with the experimental results, a partial element equivalent circuit (PEEC) model [32][33][34][35][36] is adopted to represent NI REBCO pancake coils. This model enables fast accurate simulations of the electromagnetic behaviors, as well as the thermal and mechanical behaviors of REBCO pancake coils, when coupled with thermal and elastic simulations [37,38].…”