Mechanical Comparison of Short Models of Nb<sub>3</sub> Sn Low-β Quadrupole for the Hi-Lumi LHC

Takala, E.; Ambrosio, G.; Bourcey, Nicolas; Bianchi, Laura; Cheng, D.; Ferracin, P.; Guinchard, Michael; Bermúdez, Susana Izquierdo; Mangiarotti, Franco; Pan, Heng; Pérez, Juan Carlos; Prestemon, S.; Troitino, Jose Ferradas; Vallone, Giorgio; Sequeiro, Cristina Castro; Troitino, Salvador Ferradas

doi:10.1109/tasc.2021.3057573

Cited by 4 publications

(17 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This can cause one-sided pole key to collar contact in a loaded condition. However, in practice, the contact hasn't had a significant effect on the coil stress [10].…”

Section: Shimming Planmentioning

confidence: 99%

“…The resulting coil pack is almost always different compared to the design as the coils do not exactly respect their nominal dimensions. In a rigid system, even small variations of dimension can cause considerable stress distribution deviations [10]. Moreover, the conductors get misplaced which may compromise the field quality of the magnet.…”

Section: Shimming Planmentioning

confidence: 99%

“…Blue NPK and PK curves represent the so called no pole key and pole key lines. The FE model assumes 100 µm smaller structure than nominal due to short model experience [10]. not touch the collar and (3) large pole key case where the key is in contact with the collars before the coil to collar contact.…”

Section: Key Plotsmentioning

confidence: 99%

“…Blue NPK and PK curves represent the so called no pole key and pole key lines. The FE model assumes 100 µm smaller structure than nominal due to short model experience[10].…”

mentioning

confidence: 99%

See 3 more Smart Citations

On the mechanics of MQXFB—the low-beta quadrupole for the HL-LHC

Takala

Ferracin

Lackner

et al. 2021

Supercond. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

The High Luminosity Large Hadron Collider (LHC) Project target is to reach an integrated luminosity of the LHC of 3000 fb −1 , corresponding to a factor 10 increase in collisions with respect to the current accelerator. One of the main components is the superconducting quadrupole called MQXF. It is based on Nb 3 Sn technology and has a 150 mm single aperture with a field gradient of 132.6 T m −1 . The MQXF magnets are currently in preseries production in a joint collaboration between CERN and the US-LHC Accelerator Upgrade Project. The first prototype magnet based on 7 m-long coils (MQXFBP1) was assembled and preloaded in 2019. The testing and disassembly was done in 2020. The coils were equipped with optical fiber Bragg grating (FBG) sensors. Some of the FBG values exhibited strain jumps during preload and their signals were lost during cool-down. The magnet did not reach the nominal current, quenching at 15.15 kA. At the time of writing three MQXFB magnets have been preloaded from which the second prototype is soon to be tested. The objective of this paper is to analyze the mechanical behavior of MQXFB magnets in the light of current knowledge, thanks to earlier short model experiments, as well as describe in detail the process of assembly and preload. We synthesize the mechanical theory of preload and present new considerations on symmetric/asymmetric bladder-key operations and their effects. An extensive comparison between long and short model magnets is presented. In our analysis and FE modeling we take into account the measured coil sizes that vary over position. We introduce a novel technique that allows preload homogenization over the length of the magnet after preload has been done. We analyze the role of the stainless steel shell and show its mechanical behavior. Finally, the relevant data at cold is presented and analyzed.

show abstract

“…This can cause one-sided pole key to collar contact in a loaded condition. However, in practice, the contact hasn't had a significant effect on the coil stress [10].…”

Section: Shimming Planmentioning

confidence: 99%

Section: Shimming Planmentioning

confidence: 99%

Section: Key Plotsmentioning

confidence: 99%

“…Blue NPK and PK curves represent the so called no pole key and pole key lines. The FE model assumes 100 µm smaller structure than nominal due to short model experience[10].…”

mentioning

confidence: 99%

See 2 more Smart Citations

On the mechanics of MQXFB—the low-beta quadrupole for the HL-LHC

Takala

Ferracin

Lackner

et al. 2021

Supercond. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Both two-dimensional and three-dimensional mechanical models were developed for MQXF well before this work (see figure 7), and extensively validated during the test campaign of short model magnets [79][80][81][82][83][84][85][86][87][88]. Structural elements are used to mesh the different magnet components, where the geometry of the conductor blocks (composed of many cable turns) is simplified as a homogenized solid volume.…”

Section: Model Descriptionmentioning

confidence: 99%

A methodology for the analysis of the three-dimensional mechanical behavior of a Nb₃Sn superconducting accelerator magnet during a quench

Troitino

Bajas

Bianchi

et al. 2021

Supercond. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

The fast thermal and electromagnetic transients that occur in a superconducting magnet in case of a quench have the potential of generating large mechanical stresses both in the superconducting coils and in the magnet structure. While the investigation of such quench loads should generally be conducted to ensure a safe operation of the system, its importance is greatly enlarged in the case of high-field magnets based on strain sensitive superconductors. For these, a rigorous analysis of the magnet mechanics during a quench becomes critical. The scope of this work is hence to bring, for the first time, a detailed understanding of the three-dimensional mechanical behavior of a Nb 3 Sn accelerator magnet during a quench discharge. The study relies on the use of finite element models, where various multi-domain simulations are employed together to solve the coupled physics of the problem. Our analysis elaborates on the case study of the new MQXF quadrupole magnet, currently being developed for the high-luminosity upgrade of the LHC. Notably, we could find a very good agreement between the results of the simulation and experimental data from full-scale magnet tests. The validated model confirms the appearance of new peak stresses in the superconducting coils. An increase in the most relevant transverse coil stresses of 20-40 MPa with respect to the values after magnet cool-down has been found for the examined case.

show abstract

Powering Performance and Endurance Beyond Design Limits of HL-LHC Low-Beta Quadrupole Model Magnets

Mangiarotti

Troitino

Duda

et al. 2021

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

Mechanical Comparison of Short Models of Nb₃ Sn Low-β Quadrupole for the Hi-Lumi LHC

Cited by 4 publications

References 17 publications

On the mechanics of MQXFB—the low-beta quadrupole for the HL-LHC

On the mechanics of MQXFB—the low-beta quadrupole for the HL-LHC

A methodology for the analysis of the three-dimensional mechanical behavior of a Nb₃Sn superconducting accelerator magnet during a quench

Powering Performance and Endurance Beyond Design Limits of HL-LHC Low-Beta Quadrupole Model Magnets

Contact Info

Product

Resources

About

Mechanical Comparison of Short Models of Nb3 Sn Low-β Quadrupole for the Hi-Lumi LHC

Cited by 4 publications

References 17 publications

On the mechanics of MQXFB—the low-beta quadrupole for the HL-LHC

On the mechanics of MQXFB—the low-beta quadrupole for the HL-LHC

A methodology for the analysis of the three-dimensional mechanical behavior of a Nb3Sn superconducting accelerator magnet during a quench

Powering Performance and Endurance Beyond Design Limits of HL-LHC Low-Beta Quadrupole Model Magnets

Contact Info

Product

Resources

About

Mechanical Comparison of Short Models of Nb₃ Sn Low-β Quadrupole for the Hi-Lumi LHC

A methodology for the analysis of the three-dimensional mechanical behavior of a Nb₃Sn superconducting accelerator magnet during a quench