Full-scale friction test on tilted sliding bearings for Wendelstein 7-X coils

Hathiramani, D.; Lingertat, J.; Eeten, P. van; Sochor, M.; Laux, M.; Bykov, V.; Schauer, F.; Heinemann, B.; Junghanns, P.; Brenner, Albrecht; Christoph, Zauner; Langer, Harald F.

doi:10.1016/j.fusengdes.2008.11.084

Cited by 17 publications

(15 citation statements)

References 5 publications

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“…On the inner side of the torus, where the distance between coils is rather small (a few cm) and accessibility is limited, so-called Narrow Support Elements are used. These are gliding elements that can take up contact forces up to 1.5 MN, sliding distances of up to 5 mm, and tilting up to 1 degree during magnet energization [26]. On the outboard side of the torus, so-called Lateral Support Elements have been installed providing a rigid connection.…”

Section: Structural Stability Of the Superconducting Coil Systemmentioning

confidence: 99%

“…All critical support elements have been tested, using adequate mock-ups, and benchmarked with local FE models [26,32,33,34]. 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%

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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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Section: Structural Stability Of the Superconducting Coil Systemmentioning

confidence: 99%

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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show abstract

“…Worth to mention are particularly test programs supported by intensive structural analysis for highly loaded NSEs [13,14], CSEs [15], cryolegs [16] and conductor connections [17], as well as for the mechanical quench test on the superconducting NPC type 2 under current [27,28].…”

Section: 3mentioning

confidence: 99%

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

Bykov

Schauer

Egorov

et al. 2011

Fusion Engineering and Design

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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.

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“…An extensive development and qualification test program of the narrow support elements (NSEs) [3,4] and the bolted connection (BC) of sc magnet system ( [7]) has been performed by KRP-Mechatec. The test set-ups used have been specifically developed and are able to apply biaxial loads in the MN range under cryo (77K) and vacuum (10 -6 mbar) condition, see Fig.…”

Section: Acoustic Monitoringmentioning

confidence: 99%

“…Here especially the superconducting magnetic coil system -comprising, i.a., narrow support elements (NSEs) and bolted connections -is considered. These had been tested in a full-scale test set-up with multi axial loading in the MN range at 77K and vacuum [3,4]. A smooth sliding of coated surfaces is a major requirement, as non-smooth sliding (stick-slip) excites high mechanical shock loads, which may cause a quench of the superconductor.…”

mentioning

confidence: 99%

Acoustic monitoring of superconducting magnet component test and shock simulation of coils

Christoph

Langer

Hathiramani

et al. 2009

Fusion Engineering and Design

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Monitoring of critical components is becoming a more and more important task especially in complex multidisciplinary systems as e.g. the Wendelstein 7-X [1,2]. Here especially the superconducting magnetic coil system -comprising, i.a., narrow support elements (NSEs) and bolted connections -is considered. These had been tested in a full-scale test set-up with multi axial loading in the MN range at 77K and vacuum [3,4]. A smooth sliding of coated surfaces is a major requirement, as non-smooth sliding (stick-slip) excites high mechanical shock loads, which may cause a quench of the superconductor. For an early detection of stick-slip an acoustic monitoring system has been developed and installed. Three sensor types have been compared and data analysis procedures have been developed. It has been shown that acoustic monitoring is possible under such environmental conditions at complex test set-ups and is complementary to standard sensor systems. For the development of the mechanical quench experiment, in which the actual quench sensitivityl to mechanical shock loads is investigated by impact loads, numerical simulations have been performed. For this a semi-analytical model employing a reduced modal state space model of the coil and Hertz'ian theory for the contact formulation has been set up. Based on experimental and numerical verification it proved to be an appropriate and efficient tool for simulating complex mechanical systems under transient dynamic loading. Finally, a statistical energy based model has been set up for simulating the propagation of stick-slip shocks within the complex coil system. Concluding, with the developed acoustic monitoring as well as the numerical simulation models two valuable tools for the W7-X development-test projects have been developed.

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Full-scale friction test on tilted sliding bearings for Wendelstein 7-X coils

Cited by 17 publications

References 5 publications

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

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

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

Acoustic monitoring of superconducting magnet component test and shock simulation of coils

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