Subjective reaction to vertical mechanical shocks of various waveforms
Subjective reaction to vertical mechanical shocks of various waveforms
Two laboratory studies have been conducted to assess the discomfort caused to seated male subjects by exposures to vertical whole-body mechanical shocks. The first experiment was designed to obtain judgements of the discomfort of single "up" or "down" damped sinusoidal impulses. Sixteen subjects used the method of magnitude estimation to indicate the discomfort produced by damped sine waves at nominal frequencies of 1, 4 and 16 Hz, with damping ratios of 0·125, 0·250 and 0·707 and vibration dose values ranging from 0·6 to 4·0 m s-1·75. Analysis was also conducted to determine whether the growth of discomfort with increasing magnitude was influenced by frequency, duration or direction of motion. The results suggested that a single frequency weighting and a single duration weighting is appropriate at all magnitudes. Analysis was also conducted to determine whether the discomfort depends on the frequency, duration and direction of shocks when they are presented at a constant vibration dose value using frequency weighting Wb. There was no difference between the discomfort caused by "up" and "down" shocks of the same vibration dose value, but the Wb frequency weighting slightly underestimated sensitivity to low-frequency shocks. The second experiment sought to compare two methods of evaluating stimuli containing between one and 16 repeated shocks. The vibration dose value [∫o T a4(t) dt] 1 4 and a measure of dose related to "energy", [∫o T a2(t) dt] 1 2, were employed to predict the reduction in shock magnitude required to counteract any increased discomfort with a greater number of shocks. Subjects employed the method of paired comparison. Judgements of the relative discomfort of the stimuli presented in pairs indicated that the vibration dose value provided the more accurate method of evaluating the discomfort of the shocks.
395-408
Howarth, H.V.C.
48988c97-ff47-46ba-8fe7-0aed23759a28
Griffin, M.J.
24112494-9774-40cb-91b7-5b4afe3c41b8
22 June 1991
Howarth, H.V.C.
48988c97-ff47-46ba-8fe7-0aed23759a28
Griffin, M.J.
24112494-9774-40cb-91b7-5b4afe3c41b8
Howarth, H.V.C. and Griffin, M.J.
(1991)
Subjective reaction to vertical mechanical shocks of various waveforms.
Journal of Sound and Vibration, 147 (3), .
(doi:10.1016/0022-460X(91)90488-6).
Abstract
Two laboratory studies have been conducted to assess the discomfort caused to seated male subjects by exposures to vertical whole-body mechanical shocks. The first experiment was designed to obtain judgements of the discomfort of single "up" or "down" damped sinusoidal impulses. Sixteen subjects used the method of magnitude estimation to indicate the discomfort produced by damped sine waves at nominal frequencies of 1, 4 and 16 Hz, with damping ratios of 0·125, 0·250 and 0·707 and vibration dose values ranging from 0·6 to 4·0 m s-1·75. Analysis was also conducted to determine whether the growth of discomfort with increasing magnitude was influenced by frequency, duration or direction of motion. The results suggested that a single frequency weighting and a single duration weighting is appropriate at all magnitudes. Analysis was also conducted to determine whether the discomfort depends on the frequency, duration and direction of shocks when they are presented at a constant vibration dose value using frequency weighting Wb. There was no difference between the discomfort caused by "up" and "down" shocks of the same vibration dose value, but the Wb frequency weighting slightly underestimated sensitivity to low-frequency shocks. The second experiment sought to compare two methods of evaluating stimuli containing between one and 16 repeated shocks. The vibration dose value [∫o T a4(t) dt] 1 4 and a measure of dose related to "energy", [∫o T a2(t) dt] 1 2, were employed to predict the reduction in shock magnitude required to counteract any increased discomfort with a greater number of shocks. Subjects employed the method of paired comparison. Judgements of the relative discomfort of the stimuli presented in pairs indicated that the vibration dose value provided the more accurate method of evaluating the discomfort of the shocks.
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Published date: 22 June 1991
Organisations:
Human Factors Research Unit
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Local EPrints ID: 408565
URI: http://eprints.soton.ac.uk/id/eprint/408565
ISSN: 0022-460X
PURE UUID: 2ddc3065-354e-4ee5-a6b6-0652cec4100b
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Date deposited: 23 May 2017 04:03
Last modified: 15 Mar 2024 12:23
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M.J. Griffin
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