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Almström, Mats
Publications (3 of 3) Show all publications
Kroon, M., Hagman, A., Petersson, V., Andreasson, E., Almström, M. & Jutemar, E. P. (2024). Impact testing of high-density polyethylene structure. International Journal of Impact Engineering, 192, Article ID 105033.
Open this publication in new window or tab >>Impact testing of high-density polyethylene structure
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2024 (English)In: International Journal of Impact Engineering, ISSN 0734-743X, E-ISSN 1879-3509, Vol. 192, article id 105033Article in journal (Refereed) Published
Abstract [en]

High strain -rate testing of high -density polyethylene is the focus of the present work. This testing is accomplished by two types of experimental testing: uniaxial tensile testing using standard testing technique, and impact testing of a 3D structure with non -trivial geometry. Both the uniaxial tests and the impact tests were evaluated using a material model suited for rate -dependent inelasticity of polymers that has been developed. In the uniaxial tensile tests, a maximum strain -rate of about 28/s was attained. In the impact tests, strain -rates of the order of 100/s and beyond were predicted in the analyses. The impact tests were simulated and analysed by use of finite element simulations. Coupled Eulerian-Lagrangian (CEL) analyses were employed for some of the tests where there was an interaction between the compressed structure and air trapped inside it. Overall, the simulations were able to reproduce the outcome from the experiments well. In particular, the deformation scenarios in the impact tests for different loading situations could be reproduced.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
Semi-crystalline, High-density polyethylene, Fluid-structure interaction, Visco-plasticity, Impact, Droptest
National Category
Applied Mechanics
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-131770 (URN)10.1016/j.ijimpeng.2024.105033 (DOI)001259408400001 ()2-s2.0-85196375532 (Scopus ID)
Available from: 2024-08-15 Created: 2024-08-15 Last updated: 2026-04-16Bibliographically approved
Bagni, T., Ahl, A., Almström, M., Canale, M., Dugic, I., Emilsson, F., . . . Olvegard, M. (2024). Modeling Results of the Quench Behavior of a Nb-Ti Canted-Cosine-Theta Corrector Magnet for LHC. IEEE transactions on applied superconductivity (Print), 34(5), Article ID 4001105.
Open this publication in new window or tab >>Modeling Results of the Quench Behavior of a Nb-Ti Canted-Cosine-Theta Corrector Magnet for LHC
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2024 (English)In: IEEE transactions on applied superconductivity (Print), ISSN 1051-8223, E-ISSN 1558-2515, Vol. 34, no 5, article id 4001105Article in journal (Refereed) Published
Abstract [en]

A newly designed superconducting magnet of the Canted-Cosine-Theta (CCT) type was developed as a result of a collaboration between Swedish universities (Uppsala and Linneaus) and Swedish industries. This magnet was designed to function as a replacement of the present LHC orbit corrector magnets, which are approaching their end of life due to the radiation load. As a result, the new CCT magnet was developed to be more radiation tolerant and to constitute a one-to-one replacement to the currently installed version, which is a 1 m long 70 mm double aperture dipole magnet. The final magnet, which is currently under construction, will be tested at FREIA laboratory at Uppsala University and generate a magnetic field of 3.3 T and an integrated field of 2.8 Tm at about 85 A. To examine the magnet quench behavior and to identify a suitable quench protection system, the 3D electro-magnetic and thermal behavior of the coil was modeled using the RAT-Raccoon software. Based on the simulation results, a Metrosil varistor was selected to protect the magnet during the test. In this article, we report the results of the numerical analysis. The magnet model is equipped with a spot heater to initialize the quench and the temperature and voltages are monitored during the avalanche effect. The simulated current decay and the hot-spot temperature are analyzed with a focus on the impact of quench-back on the magnet protection.

Place, publisher, year, edition, pages
IEEE, 2024
Keywords
Superconducting magnets, Superconducting cables, Solid modeling, Magnetostatics, Resistance, Electron tubes, Varistors, Accelerator magnet, CCT, Canted-Cosine-Theta, LTS superconductor, quench simulation
National Category
Subatomic Physics
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-128509 (URN)10.1109/TASC.2023.3346848 (DOI)001174032800011 ()2-s2.0-85181566683 (Scopus ID)
Available from: 2024-04-02 Created: 2024-04-02 Last updated: 2026-04-16Bibliographically approved
Pepitone, K., Kirby, G., Olvegard, M., Ahl, A., Almström, M., Dugic, I., . . . Ruber, R. (2023). Design and Fabrication of a Canted-Cosine-Theta Double Aperture Orbit Corrector Dipole for the LHC. IEEE transactions on applied superconductivity (Print), 33(5), Article ID 4000405.
Open this publication in new window or tab >>Design and Fabrication of a Canted-Cosine-Theta Double Aperture Orbit Corrector Dipole for the LHC
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2023 (English)In: IEEE transactions on applied superconductivity (Print), ISSN 1051-8223, E-ISSN 1558-2515, Vol. 33, no 5, article id 4000405Article in journal (Refereed) Published
Abstract [en]

A prototype CCT dipole magnet developed by a collaboration between Swedish universities, Swedish industry and CERN will be tested at Uppsala University. This 1 m long double-aperture magnet can provide a field strength of 3.3 T at 85 A in a 70 mm aperture with an integrated field of 2.8 Tm. It is intended to replace the current LHC orbit corrector magnets which are reaching the end of their expected life due to the radiation load. The new magnet is designed to handle the radiation dose of the upgrade to the high-luminosity LHC, which will deliver about ten times the current radiation dose. It must therefore be more resistant to radiation and meet strict requirements in terms of electrical insulation while matching the original field quality and self-protective capability, mechanical volume, and maximum excitation current. This paper will present the latest of the design and manufacturing work, including the results of simulations of the mechanical field and the mechanical stress. Details of the various tests performed before machining the parts are also presented.

Place, publisher, year, edition, pages
IEEE, 2023
National Category
Subatomic Physics
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-119505 (URN)10.1109/tasc.2023.3241571 (DOI)000936059300011 ()2-s2.0-85148414472 (Scopus ID)
Funder
European Regional Development Fund (ERDF)
Available from: 2023-02-22 Created: 2023-02-22 Last updated: 2026-04-16Bibliographically approved
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