Fatigue life assessment in lateral support element of a magnet for nuclear fusion experiment “Wendelstein 7-X”

A global analysis on one fifth of the fivefold symmetric magnet system is performed by FEM, whereas the submodelling approach is adopted to solve the crack propagation by DBEM. In particular, the adopted approach is based on the application of the superposition principle to solve a LEFM problem: the only boundary conditions for the DBEM submodel consist of tractions, calculated by the FEM global analysis and applied to the crack faces in the local submodel. The obtained speed of crack advance and crack kinking are compared with literature results to highlight the accuracy of the proposed approach together with inherent computational advantages.