Nonlinear global-local finite element analysis of a future plasma fusion experiment

For the stellarator fusion experiment, Wendelstein 7-X (W7-X), under construction at IPP, a local stress analysis of the winding package of one of the superconducting coils has been performed. The aim of the study was to get information on whether the winding pack is safe against local delamination in highly prestressed regions. The first step of the analysis was a global FE analysis to detect the highly prestressed region for the boundary conditions as input for the local analysis. The local FE analysis has been performed with a choice of boundary conditions due to the preference of nodal force loads against prescribed displacements. Although the mesh sizing between the global and local analysis is quite different, a preliminary indication of sufficient safety was achieved by a two-step calculation only. (C) 1999 Elsevier Science Ltd. All rights reserved.