Dynamic Vibration Analysis and Tribological Study of Mechanical Heat Generation Inside the Superconducting Coil for Maglev

Abstract

The purpose of this study is to reduce a mechanical heat load which is generated inside the on-board superconducting coil (SC-coil) for JR MAGLEV. The mechanical heat generation inside the SC-coil-installed inner vessel was investigated on the assumption that it is generated by the friction caused by the relative microscopic slips between the SC-coil and coil fasteners. SC-coil vibration tests and FEM analysis were performed to study the correlation between SC-coil vibration and mechanical loss (dynamic vibration analysis). A fretting wear test was performed at liquid-helium-cooled boundaries between structural components of the SC-coil (tribological study). The results of dynamic vibration analysis suggest that the frictional heat occurs in the surrounding area of the support columns in the rigid body vibration mode and in the areas where the greatest degree of bending is observed in the eigen-mode of SC-coil twisting which involves elastic deformation. In the tribological study, test results demonstrated a high possibility that the mechanical loss inside the SC-coil-installed inner vessel had occurred on the boundary between the epoxy-impregnated SC-coil and coil fasteners.