Examination of the frequency-weighting curve for accelerations measured on the seat and at the surface supporting the feet during horizontal whole-body vibrations in x- and y-directions.
In a laboratory experiment, six male subjects were exposed to sinusoidal (0.8, 1.6, 3.15, 6.3 and 12.5 Hz) or random octave band-width white noise (mid-frequencies identical to those of the sinusoidal vibrations) whole-body vibration in x- or y-directions, at six levels of magnitude (0.4, 0.8 and 1.6 m/s(2) r.m.s. non- and frequency-weighted) with two repetitions. In order to examine time effects, additional reference stimuli were used. Each subject was exposed to these 304 exposure conditions with a duration of about one minute on four different days (76 exposures per day). The subject's sensations of vibration intensity and vibration comfort were obtained by cross modality matching (length of a line). The subjects sat with an upright posture on a hard seat without backrest, hands on the thighs. The derived equivalent sensation contours suggest an underestimation of the sensation varying in extent from 2 dB to 8 dB at 1.6, 3.15, 6.3 and 12.5 Hz in comparison with the reference frequency 0.8 Hz for both types and directions of signals by the current evaluation methods according to ISO 2631-1 with the most pronounced effects revealed at the frequencies 3.15 and 6.3 Hz and at lower intensities (overall vibration total value a(ov) around 0.48 m/s(2) to 0.8 m/s(2) at the reference frequency 0.8 Hz).
Federal Institute for Occupational Safety and Health, Noldnerstrase 40-42, 10317 Berlin, Germany. schust.marianne@baua.bund.de
Marianne
M
Schust
Alexander
A
Kreisel
Helmut
H
Seidel
Ralph
R
Blüthner
D000054:Acceleration / Q000009:adverse effects*; D001696:Biomechanical Phenomena / Q000502:physiology; D015992:Body Mass Index; D005528:Foot / Q000502:physiology; D006801:Humans; D008297:Male; D009038:Motion; D010147:Pain Measurement / Q000379:methods; D011187:Posture / Q000502:physiology*; D012677:Sensation / Q000502:physiology; D014732:Vibration / Q000009:adverse effects*; D016474:Weight-Bearing / Q000502:physiology