Approximate      curve of large thin coils wound from a rectangular conductor with linear work hardening

Abstract

Approximate σθ–εθ curve of a thin coil section without reinforcement wound from a rectangular conductor exhibiting a linear behaviour after hardening is considered. The influence of the bending stress in the initially elastic coil conductors on their gradation in the plastic state is taken into account. Mechanical work done during plastic deformation of conductors near the mid-plane of the coil is estimated; when the average Lorentz hoop stress in the first energizing reaches a yield point of the coil conductor, irreversible work per unit volume of the coil body is ∼104 J m−3.