A mathematical model for thermo-mechanical response of helical wound cables

Journal article, 2026

Helical wound cables comprising helical wires and cylindrical layers are widely employed in power transmission engineering. During current transmission, the cables typically endure significant thermal loading, which can degrade their mechanical performance and service life. In this study, based on thin rod theory, thick wall theory, and Hertz theory, we propose a theoretical model for thermo-mechanicalresponse of helical wound cables, and analytical solutions are derived to predict both the global mechanical response and the local contact behavior. To validate the theoretical model, three-dimensional (3D) and two-dimensional (2D) finite element (FE) models are constructed. The theoretical predictions are compared with the FE results, demonstrating excellent agreement. Key findings reveal that arranging wires at a critical helix angle minimizes the global mechanical response under thermal load. A temperature rise induces higher interlayer contact pressure, resulting in stress concentrations at the local contact zones.Furthermore, a low helix angle of the wire significantly increases the contact pressure at the wire-insulation interface, while decreasing the contact pressure at the wire-sheath interface. This study contributes to the understanding of mechanical response mechanisms of helical wound cables under thermal load and offers new insights for their optimized design.