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High-fidelity modelling of floor-borne vibrations in axisymmetric MRI magnets using hp-finite element method

Yashwanth Sooriyakanthan, Antonio Gil Orcid Logo, Paul Ledger, Michael J. Mallett

Computer Methods in Applied Mechanics and Engineering, Volume: 447, Start page: 118385

Swansea University Authors: Yashwanth Sooriyakanthan, Antonio Gil Orcid Logo, Paul Ledger

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DOI (Published version): 10.1016/j.cma.2025.118385

Abstract

Magnetic Resonance Imaging (MRI) relies on the stability of highly uniform fields from uperconducting main coils and spatially varying fields from AC-driven gradient coils. Both types of coils are thermally separated, as the main coils are cryogenically cooled within a cryostat whilst gradient coils...

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Published in: Computer Methods in Applied Mechanics and Engineering
ISSN: 0045-7825 1879-2138
Published: Elsevier BV 2025
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa70378
Abstract: Magnetic Resonance Imaging (MRI) relies on the stability of highly uniform fields from uperconducting main coils and spatially varying fields from AC-driven gradient coils. Both types of coils are thermally separated, as the main coils are cryogenically cooled within a cryostat whilst gradient coils operate at room temperature. Externally generated floor-borne vibrations (FBV) can induce relative motion between radiation shields and coils, generating eddy currents in the shields. These in turn produce parasitic magnetic fields that compromise field homogeneity and degrade image quality. This paper presents a high-fidelity computational framework for simulating themagneto-mechanical effects of FBV in axisymmetric MRI scanners to inform the manufacturing design workflow. The approach introduces three key advancements: first, a nonlinear, fully coupled magneto-mechanical formulation solved using hp-Finite Element Methods (hp-FEM) in the open-source NGSolve framework, with a focus onoptimal interpolation order p and time step size; second, explicit mechanical modelling of both main and gradient coils, moving beyond idealised Biot-Savart type current sources; and third, the use of realistic axi-symmetric geometries with structural connectivity between coils and radiation shields in order to inform preliminary designs in Industry. A comprehensive series of numerical results is presented in order to validate the method against somebenchmarked scenarios and highlight its potential for guiding vibration mitigation and improving MRI image fidelity.
Keywords: Hp-finite elements; MRI scanners; Eddy currents; Electro-magneto-mechanics; Time vs frequency; Coupled physics; Floor borne vibrations
College: Faculty of Science and Engineering
Funders: Y. Sooriyakanthan is grateful to the UK Engineering and Physical Sciences Research Council and Siemens Healthineers for a CASE Award PhD studentship that has supported this work. A. J. Gil acknowledges the financial support of UK The Leverhulme Trust through a Leverhulme Trust Fellowship. P.D. Ledger acknowledges the financial support of the UK International Centre for Mathematical Sciences (ICMS) through a KE_Catalyst project.
Start Page: 118385

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