title: On the accurate analysis of vibroacoustics in head insert gradient coils.
abstract: To accurately analyze vibroacoustics in MR head gradient coils.
  
  
  
  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.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: Department of Radiology, Stanford University, Stanford, California, USA.
authors.forename: Simone A
authors.identifier: 0000-0002-8080-9488
authors.initials: SA
authors.lastname: Winkler
authors.affiliation: Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Alejski
authors.affiliation: Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.|The Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada.
authors.forename: Trevor
authors.initials: T
authors.lastname: Wade
authors.affiliation: Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.|The Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada.
authors.forename: Charles A
authors.initials: CA
authors.lastname: McKenzie
authors.affiliation: Department of Radiology, Stanford University, Stanford, California, USA.
authors.forename: Brian K
authors.initials: BK
authors.lastname: Rutt
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D003198:Computer Simulation; D004867:Equipment Design; D020342:Finite Element Analysis; D006257:Head / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008962:Models, Theoretical; D014732:Vibration
keywords: Lorentz damping; acoustics; gradient coil; insertable head gradient; sound pressure level; vibration; vibroacoustics