Assessment of multi-axis vibration discomfort in cabin environments: a predictive framework for seated occupants

Predicting discomfort of occupants exposed to multi-axis whole-body vibration is fundamental to optimizing the cabin environment and enhancing human-centric design in transportation systems. In this study, measurement of vibration discomfort was conducted with 13 subjects exposed to 51 single/multi-axis laboratory-designed vibration stimuli and 6 sets of stimuli recorded in real-world vehicle cabins. Firstly, the relationship between the subjective ratings for the multi-axis and single axis vibration was investigated with three methods, including the power summation method, the masking method, and the modified power summation method. It was found that the power summation method with the optimized parameters provided the best prediction for the measured discomfort ratings (RMSE = 0.284, ρ 2 = 0.87). Secondly, based on the optimal method and Stevens’ power law, a model which can predict the multi-axis vibration-induced discomfort by vibration acceleration was derived. The measured discomfort ratings demonstrated a stronger correlation with the discomfort predicted by the proposed model ( ρ 2 = 0.86) than with those generated by the method advocated in ISO 2631-1 ( ρ 2 = 0.75). These findings contribute essentially to calculating and improving environmental quality within the built environment of transport systems.