Limit analysis of narrow support elements in W7-X considering the serration effect of the stress–strain relation at 4 K

Briani, E.; Gianini, C.; Lucca, F.; Marin, A.; Fellinger, J.; Bykov, V.

doi:10.1016/j.fusengdes.2011.02.066

Cited by 10 publications

(13 citation statements)

References 6 publications

(4 reference statements)

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“… Three modes of FE simulations were carried out: 1) Conventional static analysis with the EN 1.4429 steel bridge 2) Classical limit analysis where the nominal load is increased until full plastic yielding takes place in the most loaded cross section, and 3) Limit analysis with consideration of the serration effect on the yield curve [5,6].…”

Section: Fe Analysis Resultsmentioning

confidence: 99%

Bolted coil support at the W7-X module interface

Dudek

Benndorf

Bykov

et al. 2011

Fusion Engineering and Design

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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.

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Section: Fe Analysis Resultsmentioning

confidence: 99%

Bolted coil support at the W7-X module interface

Dudek

Benndorf

Bykov

et al. 2011

Fusion Engineering and Design

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“…A special conservative analysis procedure, taking into account the structural material degradation at 4K in the form of serration effects, has been developed and implemented to accept local plastification in the support elements [35,36,37].…”

Section: Structural Stability Of the Superconducting Coil Systemmentioning

confidence: 99%

Technical challenges in the construction of the steady-state stellarator Wendelstein 7-X

Bosch¹,

Wolf²,

Andreeva³

et al. 2013

Nucl. Fusion

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The next step in the Wendelstein stellarator line is the large superconducting device Wendelstein 7-X, currently under construction in Greifswald, Germany. Steady-state operation is an intrinsic feature of stellarators, and one key element of the Wendelstein 7-X mission is to demonstrate steady-state operation under plasma conditions relevant for a fusion power plant. Steady-state operation of a fusion device, on the one hand, requires the implementation of special technologies, giving rise to technical challenges during the design, fabrication and assembly of such a device. On the other hand, also the physics development of steady-state operation at high plasma performance poses a challenge and careful preparation. The electron cyclotron resonance heating system, diagnostics, experiment control and data acquisition are prepared for plasma operation lasting 30 min. This requires many new technological approaches for plasma heating and diagnostics as well as new concepts for experiment control and data acquisition.

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“…In general, the W7-X structural design criteria for the cryogenic magnet system follow the ones developed for ITER in 2004. However, criteria for critical components, welds, handmade insulation, and other unique elements were extended and elaborated on the basis of extensive test programs and FE limit analyses by also considering the material serration effects [14]- [17].…”

Section: Structural Codes For W7-xmentioning

confidence: 99%