Effects of vertical vibration on sitting comfort in civil aviation during the cruising flight

This paper investigated the effects of vertical vibration on sitting comfort in civil aviation, with particular attention to high-frequency components (i.e. 30‒100 Hz). We generated 24 vibration stimuli at four positions (i.e. the co-pilot, front, middle, and rear seat positions) in the aircraft cabin, with magnitudes ranging from 0.05 to 2 ms^-2 r.m.s. and durations of 10 s. Twenty-four subjects (12 males and 12 females) judged the vibration discomfort using a category-ratio method. We found a significant effect of high-frequency vibration on comfort: vibration stimuli at the middle and rear seats contained more energy at high frequencies and caused significantly greater discomfort than those at the co-pilot and the front seats. However, this effect became less significant with increasing magnitudes of vibration stimuli. The discomfort predicting models provided more accurate results by amplifying weighting factors for high-frequency vibration than those using standardised weightings (i.e. W_b and W_k weightings).Practitioner summary: The severity of high-frequency vibration for sitting comfort was usually underestimated. We investigated vibration discomfort at various seat positions in an aircraft cabin. Vibration at the middle and rear seats contained more high-frequency components and caused more discomfort. This work provided accurate predicting models of discomfort using the modified weighting.