Article,
Factors affecting perception thresholds of vertical whole-body vibration in recumbent subjects: Gender and age of subjects, and vibration duration
Journal of Sound and Vibration, (2011)
Abstract
Some factors that may affect human perception thresholds of the vertical
whole-body vibrations were investigated in two laboratory experiments
with recumbent subjects. In the first experiment, the effects of
gender and age of subjects on perception were investigated with three
groups of 12 subjects, i.e., young males, young females and old males.
For continuous sinusoidal vibrations at 2, 4, 8, 16, 31.5 and 63
Hz, there were no significant differences in the perception thresholds
between male and female subjects, while the thresholds of young subjects
tended to be significantly lower than the thresholds of old subjects.
In the second experiment, the effect of vibration duration was investigated
by using sinusoidal vibrations, at the same frequencies as above,
modulated by the Hanning windows with different lengths (i.e., 0.5,
1.0, 2.0 and 4.0 s) for 12 subjects. It was found that the peak acceleration
at the threshold tended to decrease with increasing duration of vibration.
The perception thresholds were also evaluated by the running root-mean-square
(rms) acceleration and the fourth power acceleration method defined
in the current standards. The differences in the threshold of the
transient vibrations for different durations were less with the fourth
power acceleration method. Additionally, the effect of the integration
time on the threshold was investigated for the running rms acceleration
and the fourth power acceleration. It was found that the integration
time that yielded less differences in the threshold of vibrations
for different durations depended on the frequency of vibration.
