In-Line Transmissibility of the Human-Seat System Exposed to Fore-and-Aft and Vertical Vibration: Effects of Large Backrest Inclination, Fore-and-Aft Seat Position and Excitation Magnitude
摘要
With the advancement of autonomous driving levels, occupants in intelligent cockpits increasingly adopt large-backrest-inclination postures, necessitating systematic analysis of human-seat system dynamics under non-traditional sitting configurations. This study methodically investigated the effects of backrest inclination (120°, 130°, 140°, 150°), fore-and-aft seat position (front-end, central, back-end positions along the slide rail), and excitation magnitude (0.25 m/s2, 0.5 m/s2, 1 m/s2) on the in-line vibration transmissibility of the human-seat system through vibration platform tests. Based on experimental data from 12 subjects exposed to dual-axis (fore-and-aft/vertical) random vibration within the frequency range of 0.5–50 Hz, it was demonstrated that increased backrest inclination significantly attenuates low-frequency (0–5 Hz) fore-and-aft and high-frequency (15–50 Hz) vertical vibration at the backrest and headrest, while enhancing low-frequency vertical and high-frequency fore-and-aft vibration. Backward seat displacement promotes relaxation of the thigh musculature, resulting in a decrease in the resonance frequencies of thigh fore-and-aft and vertical in-line transmissibility. The resonance frequency and peak transmissibility of the human-seat system generally decrease as excitation magnitude increases, caused by the nonlinear softening of the whole-body musculature.