The Finite Element Model of Seated Whole Human Body for Vibration Investigations of Lumbar Spine in Complex System

The dynamic of human body with three-dimensional (3D) anatomical structure is not considered in the vehicle system dynamics. Moreover, the dynamic of the lumbar spine is not studied in the finite element (FE) model of the seated human, and the influence of external conditions on it is not considered. The aim of the study is to propose a comprehensive dynamic model and an analysis method to study the dynamic of the lumbar spine in a complex system. It is investigated by extracting the first six modals of different lumbar spine FE models (eight models), and the dynamic responses of the lumbar spine under white noise excitation are analyzed by random response method. It is found that the mode deformation and the resonant frequencies of the lumbar spine in vivo and vitro model are significantly different, and the peak response value of the lumbar spine is at the resonant frequency. It is concluded that the influence of vibration on the lumbar spine could be more comprehensively and visually studied by analyzing the displacement response power spectrum of FE model of the seated human body. This study provides a new method and reference for the subsequent study of the vibration behavior of the lumbar spine in complex system (especially in vehicle system dynamics), and the finding is helpful for us to find more and better protection methods of human body.