Subharmonic Resonance in Magnetic Levitation of the High-Temperature Superconducting Bulks YBa₂Cu₃O_7‐<italic> _x </italic> Under Harmonic Excitation

Study on vibration characteristics of suspension frame system for high temperature superconducting flux pinned maglev train under track irregularity harmonic excitation

“…The reference [26] shows the damp between high temperature superconductor combination and PMG exists. Additionally, the damp of suspension frame system can be added by way of the conductive material (such as copper) installed on cryogenic vessel.…”

Thermomagnetic instability and accompanied stress intensity factor jumps in type-II superconducting bulks under various magnetization processes

“…In general, due to external disturbances, the levitated body may move away from the static equilibrium point. The researchers experimentally found a series of complex nonlinear vibration behaviors closely associated with the superconducting thermomagnetic instability in levitation systems, such as quasi-periodic vibration, bifurcation and multifractal vibration, and even chaotic motion [24,25,60]. In order to reveal the physical mechanism, we consider the following simple process.…”

“…All of these studies formed a relatively systematic understanding of the thermomagnetic instability for a zero-field-cooled bulk SC magnetized in a uniform magnetic field parallel or perpendicular to its surface. However, recent experiments have confirmed that a range of other factors, such as cooling condition, magnetic field source, and magnetization history, strongly affect the flux-jump behavior [24][25][26][27]. In particular, Huang et al and Li et al observed that the vibration amplitude abruptly changes without any warning and the local temperature sharply rises under disturbance in a levitation system, consisting of a bulk SC immersed in a nonuniform magnetic field produced by PMs, and they thought that the flux jump can be regarded as the primary cause of these phenomena [24,25].…”

“…However, recent experiments have confirmed that a range of other factors, such as cooling condition, magnetic field source, and magnetization history, strongly affect the flux-jump behavior [24][25][26][27]. In particular, Huang et al and Li et al observed that the vibration amplitude abruptly changes without any warning and the local temperature sharply rises under disturbance in a levitation system, consisting of a bulk SC immersed in a nonuniform magnetic field produced by PMs, and they thought that the flux jump can be regarded as the primary cause of these phenomena [24,25]. Therefore, a complete theory to answer how the thermomagnetic instability depends upon the cooling condition, the direction or uniformity of the external magnetic field, and the residual magnetization is required.…”

Simulation Analysis and Online Monitoring of Suspension Frame of Maglev Train

“…In 1999, researchers tested and analyzed the levitation force and guiding force under field cooling and zero field-cooling conditions [15]. Because the levitation force and guiding force of an HTS maglev are nonlinear, there are also many nonlinear dynamic phenomena, such as period-doubling bifurcation, 1/2 harmonic resonance, chaos, and jump [16][17][18][19][20][21].…”