25 research outputs found
A laboratory study of the effect of posture on head movement during low frequency fore-and-aft oscillation
No full textA comparison of sickness during lateral oscillation with and without head and upper body restraint
No full textA comparison of standardised methods of evaluating rail vehicle vibration with respect to passenger discomfort
No full textEffect of foreground visual information on motion sickness caused by lateral oscillation
No full textDevelopment of a social survey questionnaire of reactions to vibration in residential buildings
No full textA social survey questionnaire has been developed to determine human responses to vibration in residential environments. The overall aim was to produce a robust methodology for obtaining responses that could be combined with vibration measurements so as to investigate dose-response relationships for vibration in residential buildings. The vibration considered included that from sources outside the control of residents (e.g., road, rail, industrial, construction). This paper describes the development of the questionnaire and explains its structure and content. A review of social surveys and field and laboratory studies of vibration and noise is included. Methods of analysing responses obtained to the questionnaire are summarised
Development of a social survey questionnaire of reactions to vibration by seated persons
No full textThe relative importance of noise and vibration from railways
No full textAn experiment was conducted to determine the subjective equivalence of railway noise and railway-induced building vibration, and hence the relative importance of the two stimuli. Six magnitudes of whole-body, vertical (z-axis) vibration and six levels of noise were presented simultaneously to each of 30 subjects in all 36 possible paired combinations. The stimuli were reproductions of the noise and vibration recorded inside a house during the passage of a train. The subjects were asked to indicate, after each presentation, which of the two stimuli (noise and vibration) they would prefer to be reduced. A seven-point scale was employed to indicate the total annoyance produced by the two stimuli. A subjective equivalence contour was determined from the levels at which 50% of the subjects preferred the reduction of noise and 50% preferred the reduction of vibration. The contour may be described by the relation LAE = 20·3 log10VDV + 89·2, where s LAE is the sound exposure level and VDV is the vibration dose value. This relation may be used to determine whether a reduction of noise or a reduction of vibration would be more beneficial to residents near railways. The total annoyance due to simultaneous noise and vibration was shown to depend on the magnitude of both stimuli.</p
Subjective reaction to vertical mechanical shocks of various waveforms
No full textTwo laboratory studies have been conducted to assess the discomfort caused to seated male subjects by exposures to vertical whole-body mechanical shocks. The first experiment was designed to obtain judgements of the discomfort of single "up" or "down" damped sinusoidal impulses. Sixteen subjects used the method of magnitude estimation to indicate the discomfort produced by damped sine waves at nominal frequencies of 1, 4 and 16 Hz, with damping ratios of 0·125, 0·250 and 0·707 and vibration dose values ranging from 0·6 to 4·0 m s-1·75. Analysis was also conducted to determine whether the growth of discomfort with increasing magnitude was influenced by frequency, duration or direction of motion. The results suggested that a single frequency weighting and a single duration weighting is appropriate at all magnitudes. Analysis was also conducted to determine whether the discomfort depends on the frequency, duration and direction of shocks when they are presented at a constant vibration dose value using frequency weighting Wb. There was no difference between the discomfort caused by "up" and "down" shocks of the same vibration dose value, but the Wb frequency weighting slightly underestimated sensitivity to low-frequency shocks. The second experiment sought to compare two methods of evaluating stimuli containing between one and 16 repeated shocks. The vibration dose value [∫o T a4(t) dt] 1 4 and a measure of dose related to "energy", [∫o T a2(t) dt] 1 2, were employed to predict the reduction in shock magnitude required to counteract any increased discomfort with a greater number of shocks. Subjects employed the method of paired comparison. Judgements of the relative discomfort of the stimuli presented in pairs indicated that the vibration dose value provided the more accurate method of evaluating the discomfort of the shocks.</p
