On the accurate analysis of vibroacoustics in head insert gradient coils.

TitleOn the accurate analysis of vibroacoustics in head insert gradient coils.
Publication TypeJournal Article
Year of Publication2017
AuthorsWinkler SA, Alejski A, Wade T, McKenzie CA, Rutt BK
JournalMagn Reson Med
Volume78
Issue4
Pagination1635-1645
Date Published2017 10
ISSN1522-2594
KeywordsAcoustics, Computer Simulation, Equipment Design, Finite Element Analysis, Head, Humans, Magnetic Resonance Imaging, Models, Theoretical, Vibration
Abstract

PURPOSE: To accurately analyze vibroacoustics in MR head gradient coils.

THEORY AND METHODS: A detailed theoretical model for gradient coil vibroacoustics, including the first description and modeling of Lorentz damping, is introduced and implemented in a multiphysics software package. Numerical finite-element method simulations were used to establish a highly accurate vibroacoustic model in head gradient coils in detail, including the newly introduced Lorentz damping effect. Vibroacoustic coupling was examined through an additional modal analysis. Thorough experimental studies were used to validate simulations.

RESULTS: Average experimental sound pressure levels (SPLs) and accelerations over the 0-3000 Hz frequency range were 97.6 dB, 98.7 dB, and 95.4 dB, as well as 20.6 g, 8.7 g, and 15.6 g for the X-, Y-, and Z-gradients, respectively. A reasonable agreement between simulations and measurements was achieved. Vibroacoustic coupling showed a coupled resonance at 2300 Hz for the Z-gradient that is responsible for a sharp peak and the highest SPL value in the acoustic spectrum.

CONCLUSION: We have developed and used more realistic multiphysics simulation methods to gain novel insights into the underlying concepts for vibroacoustics in head gradient coils, which will permit improved analyses of existing gradient coils and novel SPL reduction strategies for future gradient coil designs. Magn Reson Med 78:1635-1645, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

DOI10.1002/mrm.26543
Alternate JournalMagn Reson Med
PubMed ID27859549
PubMed Central IDPMC5435555
Grant ListK99 EB024341 / EB / NIBIB NIH HHS / United States
P41 EB015891 / EB / NIBIB NIH HHS / United States
R00 EB024341 / EB / NIBIB NIH HHS / United States
Related Institute: 
MRI Research Institute (MRIRI)

Weill Cornell Medicine
Department of Radiology
525 East 68th Street New York, NY 10065