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Fore-and-aft transmissibility of backrests: variation with height above the seat surface and non-linearity

Abdul Jalil, Nawal A. and Griffin, Michael J. (2007) Fore-and-aft transmissibility of backrests: variation with height above the seat surface and non-linearity Journal of Sound and Vibration, 299, (1-2), pp. 109-122. (doi:10.1016/j.jsv.2006.06.057).

Record type: Article


The transmissibility of a seat depends on the dynamic response of the human body (which varies between individuals, body locations, and vibration magnitudes) and the dynamic response of the seat (which varies according to seat design). In the fore-and-aft direction, the transmissibility of a seat backrest was therefore expected to vary with vertical position on the backrest. This experimental study with 12 subjects investigated how backrest transmissibility varied with both the vertical measurement position and the magnitude of vibration. The transmissibilities of the backrest of a car seat and a block of solid foam were measured at five heights above the seat surface with random fore-and-aft vibration at five magnitudes (0.1, 0.2, 0.4, 0.8 and 1.6 ms?2 rms) over the range 0.25–20 Hz. The median transmissibilities exhibited resonances in the range 4–5 Hz for the car seat and in the range 3–6 Hz for the foam. The backrests showed clear changes in transmissibility with vertical position, but there were minimal changes in the resonance frequencies. For both backrests, the transmissibilities were greatest at the middle of the backrest. The least transmissibility was measured at the top of the car seat but at the bottom of the foam backrest. At each measurement position on both backrests, the transmissibility was non-linear with vibration magnitude: the resonance frequencies and transmissibilities at resonance decreased with increasing vibration magnitude. The variations in backrest transmissibility with vertical position and with vibration magnitude were sufficiently great to affect assessments of backrest dynamic performance. The results suggest that the fore-and-aft transmissibilities of backrests should be evaluated from more than one measurement location

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Published date: 2007
Organisations: Human Sciences Group


Local EPrints ID: 45697
ISSN: 0022-460X
PURE UUID: a132d3fd-020d-4cf1-a845-873177074d21
ORCID for Michael J. Griffin: ORCID iD

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Date deposited: 17 Apr 2007
Last modified: 17 Jul 2017 15:11

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Author: Nawal A. Abdul Jalil

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