3D Finite Element Modelling of Conductor-Clamp Assemblies Under Cyclic Bending: Sensitivity Analysis of Wire Contact Coefficient of Friction

Abstract

Recent advances in numerical modelling now allow 3D analysis of complete conductor-clamp assemblies under multiaxial loading, while considering all wire interactions. In-depth studies simulating complex problems, such as wind-induced overhead conductor fatigue, are now possible. Providing detailed wire stresses and contact load distributions in the vicinity of suspension clamps, these models lead to refined conductor service life estimations. However, owing to its stranded configuration and multiple wire interactions, conductor kinematics is intricate and depends on material tribological properties. On the other hand, applications of conductor-clamp models commonly assume a uniform and constant adhesion coefficient of friction (μ_a). In reality, μ_a may vary over time with surface degradation. Therefore, numerical solutions that use a single μ_a value could provide incomplete information and thus, lead to inaccurate conclusions. Using an efficient and proven multilayered strand modelling strategy based on 3D beam-to-beam contacts, this study investigates the influence of the coefficient of friction (μ_a) on full conductor-clamp model solutions. Mapped distributions of wire stresses and local contact conditions are used to characterize the overall influence of the coefficient of friction on the model solution. Exploiting a factorial design approach, the analyses also highlight the cross-influence between the μ_a level and conductor axial tension and cyclic bending amplitude.