Friction analysis for a nonrippled superconducting energy storage structure

Two-layer low aspect ratio solenoids mounted in surface trenches are described for superconductive magnetic energy storage utility applications. A new two-layer nonrippled SMES design, in addition to rippled designs, is under study. This design has 257 two-turn pancakes. Each structure piece consists of an extruded trough, with the NbTi-AL conductor lying on its outer edge, and a simple rectangular plank. Troughs and planks are 5 meters long and overlap one another. Problems related to friction forces between troughs and planks and between conductors and troughs are considered in this study. Friction forces during cooldown, normal operations of charge and discharge, and emergency energy dump are covered. These problems are modeled by two-dimensional plates with appropriate boundary conditions. Euler's equation is employed to derive the governing equations for the friction forces. Solutions snow that the structure will slip and lock when needed due to friction and other forces.