A Comparison of Judgments of Vibration Intensity for Chest-to-Back (X Axis) and Side-to-Side (Y Axis) Exposures.
AEROSPACE MEDICAL RESEARCH LAB WRIGHT-PATTERSON AFB OHIO
Pagination or Media Count:
The subjective intensity of vibration in the two primary horizontal axes X axis, chest-to-back and Y axis, side-to-side was compared through an intensity matching procedure. Unrestrained seated subjects matched their judgments of vibration intensity in one axis X or Y by adjusting the intensity of vibration in the other axis until it was subjectively equal to the first. Each of eight subjects made a series of intensity judgments which were counterbalanced so that half of the matches were with an X-axis stimulus and a Y-axis response, and the other half were with a Y-axis stimulus and an X-axis response. Vibration was sinusoidal at 5, 7, 10, 15, 20, and 30 Hz. Peak accelerations at each frequency ranged from a lower limit of 0.1g to upper limits of 0.5 to 1.3g depending on frequency. Each vibration stimulus had a duration of 20 seconds. Results showed that, within the limits of the vibration parameters sampled, X-axis vibration was judged to be slightly but consistently more intense than Y-axis vibration. Modified author abstract
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