Experimental verification of the axial and lateral stiffness of large W7-X rectangular bellows

Abstract

___________________________________________________________________The WENDELSTEIN 7-X (W7-X) is a super-conducting helical advanced stellarator. W7-X is provided with 299 ports, which connect the plasma vessel with the outer vessel. All the ports are equipped with bellows, which, during bake-out and final adjustment, compensate the relative movements of the vessels. The lateral stiffness which was calculated with the established standard EJMA-code [1] seemed to be relatively small. This appeared to be not correct in particular for non circular bellows. The stiffness of rectangular, multi-layer bellows have then been re-calculated with the Finite Element Method (FEM) code ANSYS. The maximum difference between the FEM and EJMA code resulted to be up to 250 % in particular with movements along the longer side of the bellows. In order to clarify the differences a test-campaign with the largest rectangular bellows was performed.

Structural analysis of W7-X: Main results and critical issues

“…fig. 9) and confirmed later by experimental results for a rectangular bellows [10]. The final revision of the cryostat GM is to be completed in collaboration with ENEA (Italy) in autumn 2006.…”

Vacuum Bellows, Vacuum Piping, Cryogenic Break, and Copper Joint Failure Rate Estimates for ITER Design Use

“…There are specialized, multi-ply bellows that can be used for vacuum applications, e.g., the Kompaflex 2-ply with woven mesh between plies (see http://www.kompaflex.ch/). The Wendelstein 7-X stellarator is using a multi-ply bellows (Reich, 2007).…”

Analysis of Static Mechanical Behaviour of Metal Bellows Using Finite Element Modeling

“…The convoluted portion of an expansion joint is designed to flex when thermal movements occur in the piping system. The number of convolutions depends upon the amount of movement the bellows must accommodate or the force that must be used to accomplish this deflection [1][2][3][4].…”