Non-linear dual-axis biodynamic response to vertical whole-body vibration
Non-linear dual-axis biodynamic response to vertical whole-body vibration
Seated human subjects have been exposed to vertical whole-body vibration so as to investigate the non-linearity in their biodynamic responses and quantify the response in directions other than the direction of excitation. Twelve males were exposed to random vertical vibration in the frequency range 0.25–25 Hz at four vibration magnitudes (0.125, 0.25, 0.625, and 1.25 m s?2 r.m.s.). The subjects sat in four sitting postures having varying foot heights so as to produce differing thigh contact with the seat (feet hanging, feet supported with maximum thigh contact, feet supported with average thigh contact, and feet supported with minimum thigh contact). Forces were measured in the vertical, fore-and-aft, and lateral directions on the seat and in the vertical direction at the footrest.
The characteristic non-linear response of the human body with reducing resonance frequency at increasing vibration magnitudes was seen in all postures, but to a lesser extent with minimum thigh contact. Appreciable forces in the fore-and-aft direction also showed non-linearity, while forces in the lateral direction were low and showed no consistent trend. Forces at the feet were non-linear with a multi-resonant behaviour and were affected by the position of the legs.
The decreased non-linearity with the minimum thigh contact posture suggests the tissues of the buttocks affect the non-linearity of the body more than the tissues of the thighs. The forces in the fore-and-aft direction are consistent with the body moving in two directions when exposed to vertical vibration. The non-linear behaviour of the body, and the considerable forces in the fore–aft direction should be taken into account when optimizing vibration isolation devices.
503-523
Nawayseh, N.
1b8c9e26-3666-4a16-be48-be0ef4593231
Griffin, M.J.
24112494-9774-40cb-91b7-5b4afe3c41b8
2003
Nawayseh, N.
1b8c9e26-3666-4a16-be48-be0ef4593231
Griffin, M.J.
24112494-9774-40cb-91b7-5b4afe3c41b8
Nawayseh, N. and Griffin, M.J.
(2003)
Non-linear dual-axis biodynamic response to vertical whole-body vibration.
Journal of Sound and Vibration, 268 (3), .
(doi:10.1016/S0022-460X(03)00254-2).
Abstract
Seated human subjects have been exposed to vertical whole-body vibration so as to investigate the non-linearity in their biodynamic responses and quantify the response in directions other than the direction of excitation. Twelve males were exposed to random vertical vibration in the frequency range 0.25–25 Hz at four vibration magnitudes (0.125, 0.25, 0.625, and 1.25 m s?2 r.m.s.). The subjects sat in four sitting postures having varying foot heights so as to produce differing thigh contact with the seat (feet hanging, feet supported with maximum thigh contact, feet supported with average thigh contact, and feet supported with minimum thigh contact). Forces were measured in the vertical, fore-and-aft, and lateral directions on the seat and in the vertical direction at the footrest.
The characteristic non-linear response of the human body with reducing resonance frequency at increasing vibration magnitudes was seen in all postures, but to a lesser extent with minimum thigh contact. Appreciable forces in the fore-and-aft direction also showed non-linearity, while forces in the lateral direction were low and showed no consistent trend. Forces at the feet were non-linear with a multi-resonant behaviour and were affected by the position of the legs.
The decreased non-linearity with the minimum thigh contact posture suggests the tissues of the buttocks affect the non-linearity of the body more than the tissues of the thighs. The forces in the fore-and-aft direction are consistent with the body moving in two directions when exposed to vertical vibration. The non-linear behaviour of the body, and the considerable forces in the fore–aft direction should be taken into account when optimizing vibration isolation devices.
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Published date: 2003
Organisations:
Human Sciences Group
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Local EPrints ID: 10705
URI: http://eprints.soton.ac.uk/id/eprint/10705
ISSN: 0022-460X
PURE UUID: 78ae4d3f-2d23-4861-b0b1-74522ad014d3
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Date deposited: 09 Feb 2006
Last modified: 15 Mar 2024 05:00
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Author:
N. Nawayseh
Author:
M.J. Griffin
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