Accession Number : AD0664510

Title :   SUBJECTIVE REACTION TO DUAL FREQUENCY VIBRATION.

Descriptive Note : Technical rept.,

Corporate Author : BOEING CO WICHITA KANS WICHITA DIV

Personal Author(s) : Brumaghim,Stanley H.

Report Date : DEC 1967

Pagination or Media Count : 48

Abstract : The purpose of the study was to provide information regarding subjective reaction to dual frequency vibration. Eight male volunteers rated 'Perceptible', 'Mildly Annoying', and 'Extremely Annoying' levels of body resonant vibration (4, 5, 6, 8 and 10 cycles per second) under three conditions of background vibration. The background conditions were: (a) no background vibration, (b) 17 cycles per second (cps) vibration at 0.38 g, zero-to-peak, and (c) 17 cps vibration at 0.68 g, zero-to-peak. Under conditions of dual frequency vibration, subjects rated the effects of only the variable vibration frequencies and ignored the presence of the background vibration as much as possible. Vibration at each frequency was sinusoidal and in the vertical axis; subjects were seated. In general, subjective reaction curves obtained under no background vibration conditions were similar to those reported previously. Subjective thresholds to the variable frequencies at the 'Mildly Annoying' and 'Extremely Annoying' levels, were lowered as the severity of the background vibration was increased. The profiles of the subjective reaction curves were unchanged, in general, when ratings were made in the presence of the 0.38 g, 17 cps vibration. However, in the presence of the 0.68 g 17 cps background, 'Mildly Annoying' subjective thresholds to vibration at the body resonant frequencies were inversely related to the difference between the primary and background frequencies. The 'Extremely Annoying' subjective reaction curve again assumed the characteristic curvilinear profile. Subjects were highly consistent in making their ratings. (Author)

Descriptors :   (*AIRCRAFT CABINS, HUMAN FACTORS ENGINEERING), (*COCKPITS, HUMAN FACTORS ENGINEERING), (*AVIATION PERSONNEL, *ACCELERATION TOLERANCE), VIBRATION, FREQUENCY, THRESHOLDS(PHYSIOLOGY), PERCEPTION(PSYCHOLOGY), AIRCRAFT SEATS, PERFORMANCE(HUMAN), REACTION(PSYCHOLOGY), PILOTS, LOW ALTITUDE

Subject Categories : Aircraft
      Stress Physiology
      Human Factors Engineering & Man Machine System

Distribution Statement : APPROVED FOR PUBLIC RELEASE