Driving point mechanical impedance measurements were used to determine the dynamic response of the human head to sinusoidal vibration in the frequency range between 30 hz and 5000 hz at excitation levels of 0.98 m/sq sec and 3.4 m/sq sec. Because of the low excitation levels, the weight of the head was sufficient to couple the head to the vibration source. At 20 hz the impedance magnitude was about 790 n-s/m but increased at approximately 6 db/octave to a peak near 3500 n-s/m at 70-90 hz. Between 100 hz and 2000 hz impedance decreased by about two orders of magnitude while the apparent mass decreased by three orders of magnitude indicating good vibration isolation at higher frequencies. The impedance response contains the information for modelling the head as a dynamic system. The response of the head to vibration can be simulated by a two degree-of-freedom, mass-excited system consisting of a series connection of a small driving mass, a damper, a spring and damper in parallel and a large final mass. Parameter values, derived by computer techniques, suggest that the large mass represents the total head, the small mass the tissue in contact with the vibration input and the spring the skull stiffness. /Author/TRRL/

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  • Corporate Authors:

    Academic Press Incorporated

    Berkeley Square House, Berkeley Square
    London W1,   England 
  • Authors:
    • Smith, J B
    • SUGGS, C W
  • Publication Date: 1976-9-8

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Filing Info

  • Accession Number: 00147500
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Analytic
  • Files: ITRD, TRIS
  • Created Date: Jun 22 1977 12:00AM