The impact of accelerometer location and frequency weightings on the prediction of pleasantness ratings for vertical whole-body vibrations on an aircraft seat bench

Abstract

Noise and vibration are two physical factors that can reduce the perceived comfort of passengers during a flight. In this application context, vibrations are often measured using accelerometers placed at the seat rail or with a seat pad between the seat surface and the buttock of a sitting person. To develop pleasant aircraft cabin environments, it necessary to know which measurement location best reflects subjective ratings and whether the application of a frequency weighting as proposed in the ISO 2631 standard is beneficial. In this study, 40 participants rated the pleasantness of sinusoidal whole-body vibrations in the vertical direction while seated on a typical aircraft seat bench and listening to a synthetic broadband aircraft cabin noise over headphones. The vibration signals covered seven frequencies and four vibration levels and ratings were made on a verbally anchored scale. The results showed that an increase in vibration level leads to more unpleasant ratings for each of the tested frequencies, independent of the accelerometer position. Although the ISO frequency weighting underpredicts the ratings for high frequencies in both cases, applying it to the seat rail measurements seems to reflect the pleasantness ratings better than the seat pad measurements proposed in the ISO 2631 standard.