Structural analysis of the central support elements for the Wendelstein 7-X magnet system

The complexity of the Wendelstein 7-X mechanical support structure for the superconducting magnet system requires detailed structural analysis of its critical components. The bolted Central Support Elements (CSEs) which transfer huge electromagnetic load acting on the coil to the ring-shaped so-called Central Support Structure (CSS) are amongst the most challenging connections. Within each CSE the main components for the load transfer are bolts and wedges, stressed in radial and transversal directions, respectively. The results of detail analysis of the influence of different types of misalignment, friction factors, assembly deviations, and welding shrinkage on the opening of the connection and integrity of the welds of the most critical CSE are presented in the paper. Moreover, results of cyclic analyses aimed to investigate both the residual displacements and the plastic deformation, taking into account elasto-plastic material properties and contact interactions as sources of nonlinearity, are described.