Sensitivity of Seated Subjects to Low Frequency Random Vibrations in the Vertical Direction. Subjective Approach Using Vibrations Representative of Earthmoving Machines

Abstract

A study was conducted to compare various methods for evaluating complex vibrations. The two methods recommended by the Standard ISO 2631 were tested. A subjective equalization technique was used in which 10 seated subjects were asked to adjust the intensity of a test stimulus until they perceived a whole body sensation equivalent to a reference stimulus. The vibration stimuli were low frequency motions along the vertical axis and they were representative of earthmoving machines. They were compared to each other and to sinusoidal and third octave band random vibrations centred at the same frequencies.

The results obtained indicate that the overall frequency weighting methods are the most appropriate for the evaluation of complex vibrations. The vertical weighting curve recommended by the Standard ISO 2631 produces suitable results.

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References

Ashley

Equal annoyance contours for the effect of sinusoidal vibration on man. “Human Response to Vibration”, Meeting of the U.K. Working Group on Body Vibration, 1970, Loughborough Institute of Technology.

British Standards Institution – Draft for development: Guide to the safety aspects of human vibration experiments. 1973, BSI DD 23.

Donati

Grosjean

Mistrot

Roure

1983 – The subjective equivalence of sinusoidal and random whole body vibration in the sitting position (an experimental study using the “floating reference vibration” method). Ergonomics, 26, 251–273.

Fothergill

L.C.

Griffin

M.J.

The evaluation of discomfort produced by multiple frequency whole-body vibration. Ergonomics, 1977a, Vol.20, No.3, 263–276.

Fothergill

L.C.

Griffin

M.J.

The use of an intensity matching technique to evaluate human response to whole-body vibration. Ergonomics, 1977b, Vol.20, No.3, 249–265.

Griffin

M.J.

Subjective equivalence of sinusoidal and random whole-body vibration. Journal of the Acoustical Society of America, 1976, 60, 1140–1145.

International Standard ISO 2631 – Guide for the Evaluation of Human Exposure to Whole-Body Vibration. 1978.

International Standard ISO 7096 – Earthmoving Machinery-Operator Seat-transmitted Vibration. 1982.

Griffin

L.J.

Whitham

E.M.

Parsons

K.C.

1979 – Equivalent comfort contours. The general procedure. United Kingdom Informal Group Meeting on Human Response to Vibration, R.A.E., Farnborough.

10.

Leatherwood

J.D.

Dempsey

T.K.

Clevenson

S.A.

A design tool for estimating passenger ride discomfort within complex ride environments. Human Factors, 1980, 22, 291–312.

11.

Norme Francaise NF E 58–074 – Spécifications pour le mesurage en laboratoire des vibrations verticales transmises au conducteur par l'assise du siège. 1981.

12.

Oborne

D.J.

Humphreys

D.A.

Individual variability in human response to whole-body vibration

Official Journal of the European Economic Communities L255 – Council directive on the approximation of the laws of the Member States relating to the driver's seat on wheeled agricultural or forestry tractors. Volume 21, 18/09/1978.

13.

Rao

B.K.N.

Jones

An equal sensation study of seated subjects in three translational modes. Ergonomics, 1978, 21, 123–134.

14.

Shoenberger

R.W.

Comparison of the subjective intensity of sinusoidal, multi-frequency and random whole-body vibration. Aviat. Space Environ., 1976, Med. 47: 856–862 (1976).

15.

Shoenberger

R.W.

Intensity judgements of non sinusoidal vibrations: Support for the ISO weighting method. Aviat. Space Environ. Med. 49: 1327–1330 (1978).