Cylindrical Shell Model of Helical Type Wire Structures Accounting for Layers' Interaction

Analysis of overhead power transmission lines (OPL)involves the simulation of statics and dynamics of conductors and cables together with spiral accessories, vibration dampers, and other devices accounting for internal conductors' structures. As a typical conductor is formed by wire layers wound on each other at different angles, known issues arise in the estimates of stiffness, bearing capacity, and other properties of such structure. Indeed, the bending stiffness of the conductor depends considerably on its deformation and vary along the conductor axis as well as in time since the wire layers may slip relative to each other, and a separate wire is movable within the wire layer. On the other hand, each wire layer could be considered as an equivalent elastic anisotropic cylindrical shell on the basis of energy averaging, therefore a conductor or a spiral clamp could be modeled as a system of shells nested into each other and interacting by means of pressure and friction. This method allows one to obtain the formulae for the flexibility and stiffness of spiral structures. Some simulation results for two-layer connecting clamps with conductors including the estimates for the bearing clamp capacity limits are shown below.