An Equal Sensation Study of Seated Subjects in Three Translational Modes

Publisher Website
Google Scholar
Abstract
Equal sensation levels between sinusoidal and wide-band random vibrations were evaluated using a matching technique which employed 3 translational modes. Human subjects were exposed to 4 levels of sinusoidal vibrations, corresponding to ISO [International Standards Organization] FDP [fatiqued decreased proficiency boundary] 16 min, 25 min, 1 h and 2.5 h boundaries at 6 Hz in the vertical mode (az axis), and at 2 Hz in the back-to-chest (ax axis), and right-to-left side (ay axis) modes. Subjects rated their vibration sensations on a 10-point scale and categorized their sensations on a 4-point category scale, while taking into account the FDP durations. They then matched the random vibration to sinusoidal vibration for an equal sensation effect if exposed over such durations. The 4 matched random vibration levels were then employed as reference levels. Subjects matched various sinusoidal vibrations (1-20 Hz) to random vibrations to achieve equal sensations, again considering the stipulated FDP durations. At higher FDP levels, random vibrations when weighted with appropriate ISO weighting networks gave significantly lower r.m.s. acceleration values than sinusoidal vibration levels. Equal sensation contours revealed some difference both at low and high frequency ends, compared with ISO boundary profiles. Changes in contour profiles with acceleration levels were also observed. Significant differences between sinusoidal and random vibrations in all the 3 vibration modes were observed. Some problems encountered by some subjects during the course of the investigation were discussed.

This publication has 6 references indexed in Scilit: