Influence of seat-human contact on discomfort caused by vertical whole-body vibration under Class C road excitation

Various vehicles expose occupants to whole-body vibration (WBV), leading to subjective discomfort in seated individuals. This study investigates the impact of different seat-human contact configurations on subjective discomfort under WBV conditions. Combining the relative magnitude estimation (RME) and absolute magnitude estimation (AME) methods, a static sitting discomfort experiment was conducted before vibration testing to establish subjects' perception of discomfort levels. Under simulated Class C road excitation, five seat-human contact conditions were tested, with data collected on beats per minute (BPM), arterial oxygen saturation (SaO₂), subjective discomfort ratings, and discomfort locations. Results show a significant positive correlation (Spearman's ρ = 0.72, p = 0.002) between the frequency of BPM ‘relative peak’ and subjective discomfort occurrences. Backrest, armrest, and gripping a column reduced the frequency of BPM ‘relative peak’ by 35.3 %, 20.3 %, and 39.8 %, respectively. Headrests and armrests exhibited negative masking effects on discomfort perception, while backrests and gripping a column demonstrated positive masking effects. The optimization of seat design, especially the features of the backrest and column grip, can substantially alleviate the discomfort caused by vibration. This study provides theoretical insights for improving seat-human interaction and enhancing ride comfort.