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Title: Failure Assessments for MQXF Magnet Support Structure with a Graded Approach

Abstract

The High-Luminosity Large Hadron Collider (HLLHC) upgrade requires new quadrupoles, MQXF, to replace the present LHC inner triplets. The MQXFA magnet is the first prototype that has a 150 mm aperture and uses Nb 3Sn superconducting technology in a 4.2 m magnetic length structure. The support structure design of the MQXFA magnet is based on the bladder-and-key technology, where a relatively low pre-stress at room temperature is increased to the final preload targets during the cool-down by the differential thermal contraction of the various components. The magnet support structure components experience different load levels from pre-load to cool-down and excitation. Consequently, a few parts experience high stresses that may cause localized plastic deformations or internal fracture development. The concept presented in this paper for the failure assessment of support structures integrates nonlinear finite element analysis with detailed sub-models and fracture mechanics into an advanced engineering tool. The nonlinear FE solutions enable estimations of the structural response to the given loads, and the advanced fracture analysis with failure assessment diagram (FAD) assesses the structure safety index of results obtained from the FE model. The study describes how the MQXFA shell end segments are being optimized based on the failure analyses.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Org.:
LARP
OSTI Identifier:
1498548
Report Number(s):
FERMILAB-PUB-19-057-TD
Journal ID: ISSN 1051-8223; 1724042
Grant/Contract Number:  
AC02-07CH11359
Resource Type:
Accepted Manuscript
Journal Name:
IEEE Transactions on Applied Superconductivity
Additional Journal Information:
Journal Volume: 29; Journal Issue: 5; Journal ID: ISSN 1051-8223
Publisher:
Institute of Electrical and Electronics Engineers (IEEE)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; Fracture analysis; Nb $_{3}$ Sn magnet; mechanical analysis; superconducting magnet

Citation Formats

Pan, Heng, Anderssen, Eric C., Cheng, Daniel W., Prestemon, Soren O., and Ambrosio, Giorgio. Failure Assessments for MQXF Magnet Support Structure with a Graded Approach. United States: N. p., 2019. Web. doi:10.1109/TASC.2019.2908113.
Pan, Heng, Anderssen, Eric C., Cheng, Daniel W., Prestemon, Soren O., & Ambrosio, Giorgio. Failure Assessments for MQXF Magnet Support Structure with a Graded Approach. United States. doi:10.1109/TASC.2019.2908113.
Pan, Heng, Anderssen, Eric C., Cheng, Daniel W., Prestemon, Soren O., and Ambrosio, Giorgio. Fri . "Failure Assessments for MQXF Magnet Support Structure with a Graded Approach". United States. doi:10.1109/TASC.2019.2908113.
@article{osti_1498548,
title = {Failure Assessments for MQXF Magnet Support Structure with a Graded Approach},
author = {Pan, Heng and Anderssen, Eric C. and Cheng, Daniel W. and Prestemon, Soren O. and Ambrosio, Giorgio},
abstractNote = {The High-Luminosity Large Hadron Collider (HLLHC) upgrade requires new quadrupoles, MQXF, to replace the present LHC inner triplets. The MQXFA magnet is the first prototype that has a 150 mm aperture and uses Nb3Sn superconducting technology in a 4.2 m magnetic length structure. The support structure design of the MQXFA magnet is based on the bladder-and-key technology, where a relatively low pre-stress at room temperature is increased to the final preload targets during the cool-down by the differential thermal contraction of the various components. The magnet support structure components experience different load levels from pre-load to cool-down and excitation. Consequently, a few parts experience high stresses that may cause localized plastic deformations or internal fracture development. The concept presented in this paper for the failure assessment of support structures integrates nonlinear finite element analysis with detailed sub-models and fracture mechanics into an advanced engineering tool. The nonlinear FE solutions enable estimations of the structural response to the given loads, and the advanced fracture analysis with failure assessment diagram (FAD) assesses the structure safety index of results obtained from the FE model. The study describes how the MQXFA shell end segments are being optimized based on the failure analyses.},
doi = {10.1109/TASC.2019.2908113},
journal = {IEEE Transactions on Applied Superconductivity},
number = 5,
volume = 29,
place = {United States},
year = {2019},
month = {3}
}

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