Discomfort produced by impulsive whole-body vibration

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Abstract
This paper reports four whole‐body vibration experiments conducted to determine the effects of ’’pulse’’ duration and combinations of ’’pulses’’ of vibration on human discomfort. The first experiment investigated the variation in discomfort with vibration duration for the frequencies 4, 8, 16, and 32 Hz and durations from one cycle of motion to 4 s. The second experiment extended the results for 8‐Hz vibration to durations up to 32 s. The third experiment involved complex motions with one predominant frequency and root mean square acceleration level but differing peak levels. The final experiment investigated the effect of vibration duration at different vibration frequencies. The results of the first two experiments conflict with previous reports of a short finite integration time for human response to vibration. The data are used to devise a procedure for predicting the discomfort of the motions used in the third experiment. The procedure which is based on a ’’root‐mean‐quad’’ unit: rmq=[T−1FT0a4(t) dt]1/4 indicates that motions of the same frequency and same rms level will cause greater discomfort with increasing peak levels. The predictions are in good general agreement with the experimental results. Possible uses of the rmq unit are discussed.