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

A complex system like the large superconducting Wendelstein 7-X stellarator necessitates a dedicated organizational structure which assures permanent consistency between the requirements of its system specification and the performance attributes of all its components throughout its life time. This includes well defined processes and centrally coordinated information structures. For this purposes the department Configuration Management (CM) has recently been established at W7-X. The detailed tasks of CM for W7-X are oriented along common CM standards and comprise configuration identification, change management, configuration status accounting and configuration verification. While the assembly of W7-X is proceeding some components are still under procurement or even under design. Thus design changes and non-conformances may have a direct impact on the assembly process.Highest priority has therefore been assigned to efficient control of change and nonconformance processes which might delay the assembly schedule.

Section: Change Managementmentioning

confidence: 99%

Configuration Management for Wendelstein 7-X

Brakel

Eeten

Hartmann

et al. 2009

“…A reliable prediction of the W7-X structural behaviour is only possible with extensive finite element (FE) analyses [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…The magnet system global FE model includes the coils and their support structure, the The results of the GM FE analyses are transferred to the local models in terms of forces and moments, in terms of displacements in case sub-modelling procedures are used, or the local component model is embedded in the GM [5][6][7][8][9]26].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Structural analysis of W7-X: From design to assembly and operation

Bykov

Schauer

Egorov

et al. 2011

Self Cite

Abstract-The Wendelstein 7-X (W7-X) modular stellarator is in the assembly phase at the Max-Planck-Institut für Plasmaphysik in Greifswald, Germany. The design of the "basic machine", i.e. without in-vessel components, diagnostics and periphery, is largely completed, structural parameters such as bolt preload, initial conditions for contact elements, etc. are defined, and most of the components are manufactured and partly assembled. Therefore, the focus of structural analysis was shifted towards fast analyses of nonconformities, changes in the assembly procedure, and exploration of operational limits. Assembly-related work is expected to continue until commissioning of the machine, however, with decreasing intensity. In parallel the analysis requirements for in-vessel components, diagnostics and periphery will increase. This paper focuses on the most remarkable results, on special problems which had to be solved, on strategic issues like parameterization, complex finite element model structuring and benchmarking with alternative models in different codes, on assumptions of reasonable safety margins and expected tolerances, and on confirmation of analysis results by tests. Finally it highlights some lessons learned so far, which might be relevant also for other large fusion machines, and gives an outlook on future work.

“…Additional support at this module interface is also provided by one pair of sliding contacts between the coils [2]. The LSE D06 connection has to transmit operational loads up to 1.3 MN in axial and lateral (shear force) directions, and moments up to 0.2 MNm [3]. A nonwelded design is required due to difficult accessibility at that state of assembly, and due to requirements for the large weld seam size to cope with such enormous loads.…”

Section: Introductionmentioning

confidence: 99%

Bolted coil support at the W7-X module interface

Dudek

Benndorf

Bykov

et al. 2011

The paper presents an overview of the design, finite element (FE) analysis results, tests, and assembly strategy of the bolted connection between the coils of neighboring W7-X modules. The design is based on an accurately machined bridge and allows the accommodation of expected misalignments of the coil positions up to ±23 mm and 1 deg. The joint is capable to cope with forces up to 1.3 MN and moments up to 0.2 MNm. Loads are transmitted by a combination of form lock provided by tapered coil block shoulders, and by friction on the bottom of the blocks. Special friction-enhancing foils are inserted between the bridge bottom surfaces and coil blocks to ensure a friction factor above 0.5. Non-linear FE analyses with elastic-plastic material models show that local plastification and even slippage in spite of the initial high friction are unavoidable but stay within an acceptable margin. In parallel, machining and assembly tests have been carried out to check and simplify the design further, and to develop the manufacturing strategy.