Mechanical Analysis of a No-insulation Pancake Coil with the Overband During a Quench

The no-insulation (NI) winding approach can remarkably improve the thermal stability of high-temperature superconducting coil. However, mechanical issues have gradually become a key factor to block the development of NI magnets in recent years. This paper mainly analyzes the effect of the overband on the mechanical behaviors of an NI coil during a quench. A numerical model including a quench model combined with a three-dimensional homogeneous mechanical model is employed to study the change of stress in the coil without and with the overband during a local quench. The results show that the overband has an obvious effect on the stress distribution as the heater is located at the outer turn of the coil. Meanwhile, the values of stress in the coil are also affected by the overband. Moreover, the effects of the thickness of the overband and the location of the heater on the mechanical behaviors of the coil are also discussed. It is worth noting that the overband can remarkably reduce the hoop and axial tensile stresses of the coil during a quench