Abstract
In this study, a prediction method of the curvature and torsion of a coaxial cable, especially its shielding wires, is proposed. It seems that a shielding wire of a coaxial cable strain more highly than its core wire when the cable is bent. However, the core wire is actually broken by bending fatigue before the shielding wire even if they have the same rigidity. So, in this study, a phenomenon causing such fact is investigated. If the central axis of a wire is assumed to be twisted around a virtual cylindrical/torus surface, the shape of the wire can be described based on the second fundamental form of the surface in the differential geometry. Furthermore, the maximum principal strain, which is related to the life of the wire, can be estimated from its derived shape.
