Subjective Response to Whole-Body Vibration

Pioneer studies of subjective response to whole-body vibration were mainly directed toward construction of equal intensity contours, described by such subjective labels as “intolerable,” “alarming,” or “annoying.” In a series of more recent investigations, carried out at AFAMRL, psychophysical measurement and scaling techniques have been adapted for use in whole-body vibration experiments, primarily to evaluate the intensive dimension of various types of vibration environments. A program of research is described in which the methods of magnitude estimation and intensity matching have been used to construct a family of Z-axis equal intensity curves in the whole-body resonance frequency range; investigate subjective response for frequencies below 1 Hz; evaluate alternative methods for assessing the severity of multifrequency and random vibrations; and compare the subjective intensity of vibrations in various translational and angular modes. Results from these experiments have contributed to the expansion and improvement of whole-body vibration exposure criteria.

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Psychophysical Assessment of Whole-Body Vibration

Human Factors The Journal of the Human Factors and Ergonomics Society ◽

10.1177/001872087101300106 ◽

1971 ◽

Vol 13 (1) ◽

pp. 41-50 ◽

Cited By ~ 57

Author(s):

Richard W. Shoenberger ◽

C. Stanley Harris

Keyword(s):

Magnitude Estimation ◽

Whole Body Vibration ◽

Whole Body ◽

Subjective Response ◽

Frequency Range ◽

General Shape ◽

Subjective Intensity ◽

Straight Line ◽

Matching Procedure ◽

Body Response

Using the methods of magnitude estimation and intensity matching, curves of equal subjective vibration intensity were constructed over the frequency range from 3.5 to 20 Hz. Twenty subjects made magnitude estimations of the intensity of vibration at 0.08, 0.16, 0.24, 0.40, 0.48, and 0.56 gz with vibration at 0.32 gz serving as a standard. These intensities were judged at each of the frequencies of 3.5, 5, 7, 9, 11, 15, and 20 Hz. For each frequency, the results were plotted as straight-line functions on log-log graphs of subjective intensity against physical intensity. The slopes of the lines varied as a function of frequency, the steepest slope occurring at 5 Hz. (the frequency of greatest body response due to resonance in this axis). Additional experiments were conducted in which ten subjects matched the intensity of 9-Hz. vibration at 0.16, 0.36, and 0.56 gz with vibration at each of the other six frequencies listed above, and ten different subjects made similar equality judgments against 9-Hz. vibration at 0.08, 0.26, and 0.46 gz. Equal intensity curves derived from the magnitude estimation data show the same general shape and comparable levels as corresponding curves determined experimentally using the intensity matching procedure. These methods provide more systematic and quantitative characterizations of subjective response to vibration than previous approaches which have relied heavily on qualitative descriptions.

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