Defining Human Reaction to Whole-Body Vibration

Standardized subjective reaction levels for vibration were derived using 16 physically fit male subjects aged 25 to 40. A controlled environment, hard seat, and lap belt were used to avoid distractions and other interferences from environmental sources, to insure most complete transmission of the same input to all subjects, and to control possible frequency phase shifts between the subjects and the seat. Four vibration levels were derived: (1) Definitely Perceptible, (2) Mildly Annoying, (3) Extremely Annoying and (4) Alarming. The levels were significantly different. Each level varied in acceleration as a function of frequency. Data describing vibration effects on vision, by level, is presented to indicate the validity of the levels for use as standard vibration conditions in testing human performance.