Limit analysis of W7-X critical magnet system components with consideration of material serration effect

• Published in: Fusion engineering and design 2011-10, Vol.86 (6), p.1501-1505
• Main Authors: Ciupiński, Łukasz, Krzesiński, Grzegorz, Marek, Piotr, Zagrajek, Tomasz, Fellinger, Joris, Bykov, Victor, Dudek, Andrzej, Schauer, Felix, Panin, Anatoli
• Format: Article
• Language: English
• Subjects: Applied sciences; Austenitic stainless steels; Bearing strength; Coils; Computer simulation; Controled nuclear fusion plants; Critical components; Cryogenic magnet system; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Finite element method; Finite element models; Installations for energy generation and conversion: thermal and electrical energy; Limit analysis; Limit load; Reduction; Serration effect
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2011.03.008

The paper reports on finite element (FE) method analyses aiming at the determination of the static load bearing capacity of critical components in the support structure of superconducting coils of Wendelstein 7-X (W7-X). These components are made of austenitic stainless steel that at 4 K is known to exhibit instable plastic flow – the so-called serration effect, i.e. a scattering of the stress under increasing strain. This material behavior may significantly reduce the load bearing capacity of the components. The developed modeling approach uses a special procedure to simulate the serration effect in a conservative way. The expected reduction of the material properties due to the welding process is also taken into account. It is demonstrated that the models are capable to determine the limit loads for the critical components in a flexible and efficient way.