Abstract: The 3D finite element model of human body-seat system with driving postures including human skeleton， muscle， skin， seat， backrest and headrest was created based on the human anatomical anthropometry and the kinematics of human body. The initial boundary condition of driving postures of human body for dynamic analysis was provided by the static analysis of human body-seat system under the action of gravity. A sufficient number of modals for random response analysis were provided with the frequency extraction analysis. The model was validated by calculating the transfer function of lumbar disc to seat surface. Finally， the acceleration and stress response of lumbar disc under the action of white noise excitation of 0~20Hz on the seat bottom in the vertical direction were calculated， whose results showed that the peak response frequency of lumbar disc is less than its natural frequency as a result of seat coupling effect. The method can be used to replace experiments to research the response of human body-seat systems with different schemes.

Key words: human modeling, human body-seat system, power density spectrum, random response analysis, lumbar disc