Dynamic Characteristics of a Standing Human on a SDOF Structure

This paper studies the dynamic characteristics of a human-structure system. The integrative modeling (i.e., a continuous bar represents a body standing on a Single Degree-Of-Freedom (SDOF) structure) is used to derive the coupled Two Degree-Of-Freedom (TDOF) system when the fundamental mode of the bar is considered only. In the new TDOF system, the mass matrix is full, which is different from the conventional TDOF system where the mass matrix is diagonal. The solutions of the natural frequencies, damped natural frequencies, resonant frequencies, damping ratios and displacement spectra of the new TDOF body-structure system are derived. A parametric study is conducted to examine the effects of different bar-body models, the mass ratio and frequency ratio on the three types of frequencies (natural, damped natural and resonant frequencies) of the new system. It is found that the bar-body models have slight effects on the three types of frequencies. The first natural frequency of the human-structure system decreases with the increase of the mass ratio. However, the second natural frequency of the system increases with the increase of the mass ratio. Both natural frequencies of the system increase with the increase of the frequency ratio.