Effect of Tube Thicknesses on Electromagnetic Drag and Guidance Forces for Hyperloop With HTS Magnets

This article follows previous research on electromagnetic (EM) drag and guidance forces between high-temperature superconducting (HTS) magnets and tube infrastructure for Hyperloop. It was found that large attractive forces in the guidance direction of decreasing horizontal stiffness, $\mathbf {k}_{\mathbf {x}}$ , which reduce the dynamic stability of pods, are generated between HTS magnets and AISI 1010 tubes under a pod velocity, v, of 300 km/h. To mitigate this issue, high-manganese (Hi-Mn) tubes generating repulsive guidance forces were used when v was below 300 km/h, while AISI 1010 tubes were adopted over 300 km/h to minimize the construction cost of tubes and guarantee the increase in $\mathbf {k}_{\mathbf {x}}$ . However, EM drag forces between the HTS magnet and Hi-Mn tubes under v of 100 km/h are nearly twice that of AISI 1010 tubes. This problem may cause a significant reduction in the propulsion efficiency, especially when pods are running at constant v under 100 km/h, e.g., in low-speed branch lines. To address this challenge, the effect of AISI 1010 and Hi-Mn tube thicknesses on EM drag and guidance forces was comprehensively analyzed in this article. With full-scale 3-D FEA simulation results, the optimal tube thicknesses and tube materials corresponding to the operating velocities were obtained to ensure minimal EM drag forces and an increase in $\mathbf {k}_{\mathbf {x}}$ simultaneously. Specifically, the EM drag forces generated by Hi-Mn tubes could be significantly reduced by decreasing $\mathbf {d}_{\mathbf {tube}}$ under v of 100 km/h, while the repulsive forces in the guidance direction were first observed by adopting AISI 1010 tube thicknesses of 20 and 40 mm at v of 200 km/h. Finally, the structural effect of the EM drags and guidance forces on steel tubes was analyzed using FEA simulations, and it was found that the tube thicknesses should be thicker than 20 mm to meet the minimum deformation of 10 mm along the x-direction.